I've been on both sides. And I think it's mainly a pride thing, you didn't ask for help, and weren't really looking for it. If you died, oh well, you probably learned a lesson or limitation. Help also can drop xp, and that matters to some. And on the other hand, I'd like to 'thank' those that just watched me die, thank them thoroughly. I've also helped people and received no acknowledgement. But while it irks me a bit, I gave the help of my own free will, and really it's what I've come to expect in wow, if not the net as a whole.