I'm maybe going to be slightly against the grain here, but I try my best to understand the many sexual orientations there seem to be. But I really disagree with people having to come out, if I went for a job in an office they couldn't ask me my sexual orientation, it's my business, & I get the role model example but why should anyone have to announce their sexual preference to the world?. You don't meet new friends & say hi I'm marvel & I'm gay/straight etc.. let people live their best lives, I hate that Gareth Thomas had to come out because of the papers, it really grates that anyone should be forced into something.
Human sexuality¹ are infinitely complicated, and don't have to make sense to anyone other than the person themselves. They're valid even if they make no sense to other people. If a man wants to say he's "straight but I like to be fucked by men" or a woman wants to say she's "straight with a fetish for big boobs", to use two examples I've actually heard, then that's up to them.
And no one should have to come out, but they should also feel like they can if they want. On a personal level I've never been that bothered by telling people things like that², but not everyone feels the same way. As far as celebrities go, it's a little bit different, really. If someone is genuinely private and says nothing about their private life, then yeah, leaving them alone is probably the best bet (although, to be honest, speculation about it is still okay, as long as it doesn't descend into stalkerish behaviour). When you get into either bearding or outright hypocrisy, then that's a whole different matter. Stalkerish behaviour is still wrong though.
¹And, indeed, gender expression.
²I always joke that it's a coin toss whether I tell people I'm bisexual or have Asperger's Syndrome first lol.