You know what, lets make this one simple.
I'm a member of a plural system, origin of which is unknown but yet here i exist. Like it or not.
Along with that tidbit, the physical body in which this system resides is mid-transition and is able
to get by quite well with the chosen physical appearance.
So, that being said, the fact that we are 'multiple' and also transgendered as a whole seems to throw
out the whole notion that they've even remotely mutually exclusive. I mean, last i checked, causation
doesn't matter one bit to recieving treatment for "GID", just the fact that the dysphoria exists is enough.
As for 'valid personalities', i suppose that little bit is in question itself. Because most of the systems i know prefer to have their members referred to as people, not personalities. As such, again, the suggestion that GID can't coexist quite easily with the existance of plurality seems a bit silly. Since it would be quite obvious that a person who's identity doesn't match their physical sex and is distressed by said fact would have by definition dysphoria.
The tidbit about the 'condition' causing the gender issues is also just a bit off in my book. It causes the gender issues just about as much as the fact that someone breathes causes their gender issues since there's been no definitive proof of any causation for GID.
About this being a psych issue though, that seems like a fairly abject dismissal of the reality of the situation. I think many people here would be quite offended if their identity was simply dismissed to the level of a 'psych issue' that needs to be cured and cut loose.
Does it make things difficult? Yup, sure as hell does. But that doesn't mean it shouldn't be treated as the reality it is either or dismissed as some type of fantasy any more than the desire to have a bodysex different from the one you may currently possess.
I think a bit of research into plurality may be in order also, and you'd see that there are quite a few parallels to be drawn between DID and GID and the pushes to get both changed and modified to reflect what's really going on rather than what some psych without any first hand experience with the issue dreams up.
I apologise for being a bit rambly and going a bit off on a tangent, completely exhausted but i think this needed to be said from a first hand perspective.