In the modern age, is outing gay people right or wrong?

You leave the busy nightclub to get some fresh air. Once outside, you look up and immediately see a well-known male celebrity in an alleyway kissing another man. You instantly recognise them as a well-respected person and public figure who publicly presents themselves as heterosexual. You know that if he were to come out, it would be an inspiration for many young gay men and you are confused as to why he is hiding this from the world. Should you out this gay man? What do you do?