Discrimination is when someone treats another person unfairly or unkindly for reasons that do not make sense. Imagine if you were playing with your friends and someone said, "I don't want to play with you because you have brown hair." That wouldn't make any sense because there is nothing wrong with having brown hair. Discrimination against gay men is like that, but it happens because some people don't think it's okay for a man to love another man.
Sometimes people who discriminate against gay men might say mean things to them or try to hurt them. They might treat them badly at school or work, or even try to stop them from getting married or having the same rights as other people. This is very unfair and can make gay men feel sad and scared, but it's important to know that being gay is just as good as being straight and there is nothing wrong with it at all.
It's important that we treat everyone with kindness and respect, even if they are different from us. We should be kind to gay men and accept them just like we do with our other friends and family members. We all deserve to be treated fairly and to be happy just the way we are.