People also rage about being panic knifed in a shooter known for being a twitch, e.g. drop shotting and jump shooting. Compare BO2 to MW2 for knifing. Also, people hate being killed by shotguns that have a range more than 1m, while using SMGs themselves.
It's probably only popular in the US. I don't notice much of it in UK lobbies. It's happens a little bit with weapon variety. If I see good representation of Accuracy International rifles I know I'm in a lobby predominantly from the UK.
It's only going to get worse and not just with QS, come the morning of December 25th and millions of little brats will have a shiny new copy of Ghosts so expect much more cheating, hacking and especially boosting.