Being gay is not an act but living the gay, black, trans, Asian, whatever experience inform a persons decisions. There are things an actor can NEVER know because it’s not a part of their lives.
They try to represent a character as accurately as possible but most times still come up short because they don’t KNOW what the character they are portraying actually deals with, how they feel, how their lives experiences effect them.
Understanding doesn’t equal knowing. This is what having the proper onscreen representation is about. Not just having a gay or black or whatever character in a story but having it accurately portrayed and represented by someone from that group is the rub.