If it’s true that one’s sexuality “effects [sic] your existence, perspective, and experience in this world…” then obviously the same can be said of straight people. True enough. So logically this is an argument that gay actors shouldn’t be able to play anyone but gay characters. Can’t really have it both ways.
It’s a slippery slope people walk when only those who are exactly like the character (gay, fat, etc, etc, etc) can play it. Take it to its logical conclusion, and where does that leave theatre?