I get it. Nobody likes being called out, criticized, or told they need to change something. However, I've always had a problem with this particular response. IMHO, "Y'all do it, too" is the laziest, weakest, most immature response to anything, ever. Here's why I believe this so strongly:
We already know that.
Every time I read a YDIT response, my inner sailor wants to say, "No $#!t, Sherlock". 9 times out of 9.5, it goes without saying that the other group does "it" as well. And unless the they're completely out of touch with reality, the author knew this when they wrote it. They just weren't talking about that group at that moment, for whatever reason, but we'll get to that momentarily. Some may be all too ready to shout that the author is a hypocrite, which could be the case, but isn't necessarily. But yes, under most circumstances, either side has been guilty of whatever "it" is. Both men and women cheat. People of all races have had some sort of prejudice towards some others. Both the major political parties in the US have used smear campaigns and done other shady things. I could keep going with this, of course, but you get the picture. You're not stating anything new by saying YDIT. You're not covering any new ground. All you're doing is putting on your "Captain Obvious" cosplay and getting fully into character.
It doesn't justify anything.
Regardless of who did what first (with most things, it'd be pretty impossible to trace back to exactly who), neither side doing something foul justifies the same for the other. If you think that it does and therefore are using it as an excuse to keep doing whatever "it" is, all you're doing is keeping the cycle going, adding gasoline to the bonfire.
You're "All lives matter"-ing the situation.
When you respond with YDIT, you're also doing a couple of similar things. First, you're invalidating that person's experience. This is a very mild example, but let's just pretend I went out salsa dancing last night, and I danced with an unusually high amount of women who had, as I like to call it, "scorpion hands", where they put a vice grip on their partners hands, which is very uncomfortable. In my frustration, I may post a Facebook status saying "Ladies, please don't give your partner scorpion hands". Though this would be the exception among my circle of FB friends, it wouldn't surprise me to see someone reply with "well, leads do this to ladies all the time." But if I, as a lead, am not guilty of this (I'm not), what does that have to do with me and my particular situation? So I'm not allowed to feel bad about this because other guys who aren't me have done this to their partners? And I'm keenly aware that guys do it too, and I address both if I'm teaching a class. But if I'm venting about what has happened to me, I'm not talking about everyone, and I honestly don't feel I need to. If a woman posted the opposite, I'm not going to jump into her comments with "well, ladies do this too, ya know."
I'm taking a slight detour with this next point, but also, when you reply with YDIT (or its close cousins, "What about ___" and "It happens to us, too"), you're vilifying the person for having the "audacity" to only speak about their experience and not include every other possible group who has also experienced it. That's why I and several other associates of mine have turned #AllLivesMatter into a verb. You're "all lives matter"-ing someone's post when you interject with "well, we go through this, too", effectively derailing the conversation. If someone is speaking about their personal experience, or if they're focusing on one group or another, often times it's for a reason. For example, both men and women get abused, harassed, and sexually assaulted. However, #metoo focused on women because they are far more often the victims. No reasonable woman who posted #metoo was inherently saying "this never happens to men", nor did any reasonable man assume that. Also, there's a separate "Breast Cancer Awareness Month" and "Prostate Health Awareness Month" as opposed to just a general "Cancer Awareness Month" because, although they are similar, they each have nuances that deserve specific attention, and therefore it would be a disservice to lump them all together. So, it'd be very tasteless to say "what about breast cancer?" when someone decides to post about prostate cancer. Obviously, not every situation that gets all lives mattered is as heavy as the examples I just gave, but hopefully you catch my drift.
I'm taking a slight detour with this next point, but also, when you reply with YDIT (or its close cousins, "What about ___" and "It happens to us, too"), you're vilifying the person for having the "audacity" to only speak about their experience and not include every other possible group who has also experienced it. That's why I and several other associates of mine have turned #AllLivesMatter into a verb. You're "all lives matter"-ing someone's post when you interject with "well, we go through this, too", effectively derailing the conversation. If someone is speaking about their personal experience, or if they're focusing on one group or another, often times it's for a reason. For example, both men and women get abused, harassed, and sexually assaulted. However, #metoo focused on women because they are far more often the victims. No reasonable woman who posted #metoo was inherently saying "this never happens to men", nor did any reasonable man assume that. Also, there's a separate "Breast Cancer Awareness Month" and "Prostate Health Awareness Month" as opposed to just a general "Cancer Awareness Month" because, although they are similar, they each have nuances that deserve specific attention, and therefore it would be a disservice to lump them all together. So, it'd be very tasteless to say "what about breast cancer?" when someone decides to post about prostate cancer. Obviously, not every situation that gets all lives mattered is as heavy as the examples I just gave, but hopefully you catch my drift.
Your defensiveness and lack of maturity is showing.
I would only apply this in the case that said criticism is constructive and not just random (insert group here)-bashing, but when you comment with YDIT, all you're doing is being defensive. You're using it as a deflection to avoid addressing the issue at hand. Even those of us who are very self-aware still don't always notice our flaws and correct them without someone calling them to our attention. Personally, I know that, even though I consider myself to be pretty self-aware, I know many of my former flaws would still exist if it weren't for others talking to me about them, and my current ones would be worse than they are. Just my opinion, but those of us who are mature are able to move past our initial feeling of "how dare you call me out?!" and see that "ok, maybe I do need to work on that." If your immediate response to a criticism or offering up of advice is to "clap back" with YDIT, you're just showing your lack of maturity and self responsibility. It's immaturity that makes us say "well, if you're gonna call me out, you'd better be calling out everybody else who does this, too".
At the end of the day, there are always going to be posts about particular topics, and they aren't all going to cover all sides of everything. And quite frankly, I don't think they need to. I don't think people should have to walk on eggshells, worrying that someone will get all in their feelings if their post doesn't cover every possible angle. Maybe I'm asking too much, but I think people should have the maturity to be able to read a post about a group they're a member of and not take it personally, especially if the criticism doesn't apply to them specifically. Unless explicitly stated, the author isn't saying "all (insert group)", so if it doesn't apply, no need to get defensive. Hit dogs won't holler. But if that shoe fits, tie 'em up tight and get to runnin'. See if there's a lesson you can learn about how your behavior makes others feel.
At the end of the day, there are always going to be posts about particular topics, and they aren't all going to cover all sides of everything. And quite frankly, I don't think they need to. I don't think people should have to walk on eggshells, worrying that someone will get all in their feelings if their post doesn't cover every possible angle. Maybe I'm asking too much, but I think people should have the maturity to be able to read a post about a group they're a member of and not take it personally, especially if the criticism doesn't apply to them specifically. Unless explicitly stated, the author isn't saying "all (insert group)", so if it doesn't apply, no need to get defensive. Hit dogs won't holler. But if that shoe fits, tie 'em up tight and get to runnin'. See if there's a lesson you can learn about how your behavior makes others feel.