On the subject of endogenic plurality, I find it really horrific the way the anti-endo movement has reared its head. It's like these people figured out that being anti self-dx was being too widely recognized as the cruel ideology it is, so they needed to find something a bit more subtly cruel.
"You can't be plural without trauma" There is no such thing as a non-traumatized person. We live in a society built to torment and traumatize people, starting with the fact that you have to spend the first [x] amount of years in your life being legally owned by another human being. So what you really have to be saying to have this statement make any sort of (even twisted) sense is "you can't be plural if you're not traumatized enough." How do you decide who is? If you don't decide, who does?
Does the person themself decide? If they do, how can you be sure that they'll recognize their experiences as traumatic? And how are you going to treat them if they don't? For the longest time I hadn't recognized what I went through as being traumatic. I thought it was just a fact of life, an unfair fact but a fact nonetheless. Would you have told me that I can't be plural if I had expressed that to you back then?
Does a diagnosis decide? What about the people who've been abused at the hands of the psych industry? What about the marginalized groups who are known to have their struggles undermined and dismissed by the psych industry? What about the people who've never been able to access those resources? What about the kids who are classified as too young to receive a medical diagnosis? Should they be gatekept from plurality because they didn't get the right piece of paper?
Where is the line drawn between people who are traumatized enough to be plural, and the people who aren't? Is there qualifications for how badly you have to be abused before you're allowed to describe yourself as plural?
Even if you did come up with an answer to all of these questions, how do you plan to enforce this boundary? Are you going to go around asking every plural person you meet to describe their traumatic experiences to you so you can make sure they're on the right side of the line you drew? Or are you just going to leave it be because you don't actually care? At that point, why even try to draw the line other than to be cruel to other people?
Because that's the point.