i guess people are bored for lack of new content, and go in lower zones to spend time..
it will get better as you level. It will become much more difficult for an 80 to kill your 5 man group as you progress.
endure, keep track of names, and get your revenge later :-)

Then again, i kinda understand them, it must be diffcult to resist the temptation of wtfpwn a group of 5 in 1 go.