Some tryhards rage quite a bit if they do really well and their team still loses. I imagine most of your negative rating is just those people wanting to set you as 'avoid this player' because their team lost, and language is the easiest for them to quickly hit. It is kind of cutthroat, but people do, for whatever reason, take this game very seriously.
I'm sure that hacks happen, but I'm also sure that people claim hackzor much more than what actually happens. I've heard of so many complaints about an opponent hacking when they clearly weren't. In this case, it's "they take this game and seriously overaccuse people of hacking it"
According to Ban Candy ,She can't believe there are so many Cheaters in MW 3 and is at least 17 days behind in Reports.
Never came across a hacker but came across countless boosters ,security on xbox is good.