name-calling and condescending, derogatory remarks aimed directly at the person that is defending an idea or opinion or belief that you don't agree with. That is the behavior at question.
Thanks for clarifying. That is of course inappropriate.
I believe it is not only acceptable, but indeed appropriate to point out inconsistencies and errors in beliefs as well as to correct false ones. But that does not mean that the one doing the correcting should try to make the other person feel bad nor should they attack them personally.
On the other hand, I've both seen and been the object of personal attacks as a result of merely disagreeing with other posters on this forum. I have tried to get them to see that I disagreed with their content, ideas or actions, but they took it personally and responded with personal attacks. This betrays an immaturity on their part which is totally not conducive to rigorous intellectual discourse.
