If someone is offended by reading ideas that run counter to one's beliefs, oh well. If one takes offence in a discussion of religious ideas, that sometimes is a sign that the person has encountered an idea that opposes his/her belief system and that cannot be reconcilled. The confusion can trigger defense mehanisms that result in emotional response.
So if you can't stand the heat, then well, you know the rest. I think I have wasted enough life as a JW that I am entiled to have strong opinions toward them. However if someone posts stricktly for the purpose of offending someone, I would consider it rude.