Rii
Rear Admiral
Nothing in the "new reality" would account for this. You are either born gay or not. Period.
Nothing in the "new reality" accounts for the radical changes in the appearance of each of the characters either, so what? Folks should embrace this opportunity to redefine Trek, not cling to it at every opportunity.

Incidentally, it's been a while since I've seen TOS but I don't recall Sulu ever explicitly being defined as heterosexual.