> I think that in any human-2-human interaction, we are all entitled to at least basic courtesy

Why? If you are hostile towards me, mock me, or attack me or are in some other way a douche towards me, I reserve the right to handle you in any way that I want to. My opinion of you has to be earned, just like respect. There is no entitlement for my basic courtesy. I am willing to give everyone the benefit of doubt at the beginning, and extend courtesy, but "entitlement"? no. You do not get to decide what I think or how I feel about you.