I got kicked from an LFR one time in 5.1, but for kind of the opposite reason.
I was dicking around on my combat rogue, running ToES LFR. On Protectors, I decided to keep blade flurry on and dps as hard as I could. Flask, pots, food, etc. Needless to say, I topped meters by a silly margin. The second guy on the dps meter was a lock with a few pieces of heroic raid gear. He did some impressive damage as well, dwarfing everyone else on the list except me. My rogue was all lfr/valor gear.
I guess he got butthurt that he didn't have the biggest numbers in lollfr and was beat by someone with mediocre gear. About a quarter of the way into the boss he figured out what I was doing and started to try and call for a wipe, claiming that I was hurting the raid by cleaving. No one listened to him about wiping, but the entire time he just went on and on about how I'm trash. I never said a word, but it was clear I hurt his precious ego. He was spamming me in whispers with "BLADE FLURRY ISN'T SKILL," lol. I knew I wasn't helping the raid by cleaving, but it's LFR. I just wanted to see what kind of numbers I could get on the meter for the fun of it. Meh.
I was kicked after the boss. No one but the lock had said anything negative about me, from what I remember. But I guess his incessant bitching swayed them over. It was definitely a head-scratching moment. How dare I have fun on easy mode. I should have just done as much dps as the healers and blended in. But yeah, LFR people suck (mostly).