That doesn't really chance GP's argument. There are a lot of countries where it's not illegal. Should it be? A lot of people would disagree with banning every kind of insensitive behaviour by law. And yet a conference might not want to host that kind of behaviour in their event, and want to make clear what kind of behaviour they find acceptable or unacceptable. Especially for such temporary events, it's useful to have clear lines and guidelines about what's acceptable and what not, especially in a society where some people don't seem to know or care. But that doesn't mean everything should immediately be legislated by law.