I'm of two minds on the should-gay-roles-go-mainly/exclusively-to-gay-actors? question.

On the one hand, I remember when gay roles (what few existed, anyway) pretty much always went to straight actors... because gay actors were so closeted they didn't dare take them. (What if audiences found them all too convincing? And started to wonder if it was entirely a matter of acting skill...?) Hell, even the straights often wouldn't either, unless they were the type with unimpeachably-Kinsey-0 public credentials. So LGB actors being out enough to not only play, but even be preferred for, LGB roles means a lot to me. It's a legitimate sign of how far we've come.

But on the other hand... that so many straight actors are now open to playing gay roles is also good news for us, you know? It means that "gay" is no longer seen as unquestionably stigmatized. Something to shun association with, lest it give you cooties. Which makes me reluctant to discourage THAT, either.

Also, there's a potential downside to the "play only what you are" rule for gay actors, since it suggests that THEY have no business portraying STRAIGHT characters... which would exclude them from the vast majority of roles. As well as implying that LGB people are inherently super-different from heterosexuals, in a "we just can't EVER understand each other! never the twain shall meet! etc." way-- not a mindset that tends to bode well for us.

As for authenticity, well... I'm not sure how much that even has to do with acting, really. Because whether your own life parallels the role, or you're actually experiencing the emotions scripted for the scene, means nothing; all that matters is the ability to convey what your character is feeling in a way that the audience can recognize and relate to. And this screen language is quite stylized, unlike reality (how we as individuals express emotion can be pretty idiosyncratic); for the public-at-large to interpret it reliably, that's a must. So what we're talking here is less authenticity than a technical skill. Since, with acting, the illusion of authenticity often "reads" as more authentic than... the real thing.

However, I should note here that my "gaydar" pretty much ain't fer shit, which may well affect your opinion of this entire analysis!