I'm going to laugh at a sign that isn't meant to be a joke.
Why do you want to laugh at a sign?
Because I think it's funny.
You think a lot of things are funny. It's not cool to laugh at something that is meant to be serious.
Whatever, I'll do it as I want.
Clearly, but I am here to tell you it is wrong. If you continue to do this you should expect backlash from others.