I don’t know about this. The whole point of being a good actor is to do a believable portrayal. The idea is to play something you are not. I get the “x is taking a role that could have been played by a minority” argument but there is more to it than that. Having someone well-known (regardless of sexuality) playing a gay or trans role brings the title more publicity and more attention is brought to LGTB issues. I’m not saying all LGTB characters therefore should be played by the most well-known actors but just that there is some value “for the cause” when it happens. It’s not per default a negative. Brokeback Mountain would not have had the impact (or wide release) it had if the actors hadn‘t been as well-known. All actors should be allowed to play all roles. That’s what acting is about.