tell people they are wrong...How come I don't get any???
Am I not curt? Am I not opinionated?
What must I do!?
You're wrong.
You have to tell them they're wrong and then go on to explain in detail how they're wrong. The right way to do that is to directly quote from some key document (like a rule book). You can also just resort to a lot of words you pulled out of your @$$, but that may actually being deserving of at least some level of negative reply.
=)