Its sometimes very surprising to know that the differences in values could be so hugely different between people living in the same society. However, there pose no problem if people respect this to be a fact and lean to accept this is the case by not hurting and imposing a certain judgment onto them (provided they don't hurt anyone and acting within the framework of the law).
Let's accept the possibility that not everyone is as fortunate as us and such mishap may have developed a dark side for him/her. Maybe, their rude/unacceptable comments could be comprehend as a call crying for help. Yet I agreed with you that everyone have tolerance limits and he/she had crossed that line. I just hope that the quality of internet security is sufficient to protect our identity such that we could express freely for ourselves.