You know what, I’m kind of won over to that point in the case of trans people. I don’t think orientation is a problem at all in the film industry these days and I don’t think it needs to be considered for a role. But I think trans could potentially be similar to race. The exception would be in the case of a low budget movie where perhaps the director can’t find a trans actor, but in Hollywood and big-budget things I think I get it now.
The same thing with trans actors goes for disabled people too.
The sexual orientation thing isn’t really as pressing a concern (as you do see gay actors play straight roles fairly often) but I do think it’s fair in general that people are somewhat miffed when non-hetero characters are played by hetero actors, only because gay characters are still somewhat rare.