Because the internet, and particularly chat rooms like this are...

Because the internet, and particularly chat rooms like this are virtual cesspools where people have the freedom to behave exactly as they are, without the moderating effect of real life social norms that tend to curb people's natural inclinations. It's a sandpit for obnoxious adult tools to play with each other, and indulge in their most childish impulses.
Imagine what kind of person gleans an immense sense of satisfaction from baiting and bickering with others via a keyboard? And coming back again and again to do so. It's truly pathetic.
Sadly, HotCopper, which was once a really great forum, is now infested with this idiocy. My Ignore list grows, but because the threads are so clogged with nonsense these days, it's becoming harder to follow any logical or sequential conversation. The moderators probably need to sweep through with a big broom and reset it all. Part of the problem is though, that so many people seem to think that this a normal way of communicating, they will be banning thousands of members.
I'd be fine with that personally though.