Don't know which game modes of Hardcore you play but some modes may have fewer scrotes to put up with. May be Kill Confirmed? Be careful of CTF because I've heard of people shooting teammates' Bouncing Betties near their flag to get themselves killed so that you get kicked...
i've said it before and i'll say it again
it should be a bannable and reportable offense when people on purpose try to mess with your gaming experience like that
it got big in mw3 with the SUK vids on yt it seems, and since then it's gotten really annoying
atleast you can avoid them through their GT for being an unsportive player