Is there an "are we dating the same guy?" group for every city? Sure I believe that. Do 100% of those groups commit Doxing? Well, that I'm not so sure of.

In fact, I've literally never heard of that before, it doesn't sound like the objective of the group. So I googled it and I found one case where a guy is arguing that people in the group manipulated his messages and so he's suing Meta for Doxing.

Also, if you read closely you might be confused like I was. Defamation is not Doxing.

So if you have evidence of Doxing in these groups I would love to see it.