Personally, I laugh when I hear 10 year old kids say this completely out of context. They obviously do not know the meaning of Internet trolling.
But as for not-10-year-old kids, the phrase has become so mainstream now it means nothing. Same with the word 'trolling' itself.
Like:
"Oh hey guys, I'm new to this game, so don't get upset if I do bad!"
[later on; doing bad]
"Sorry guys! That was my fault, I know what to do now though! :) "
"lolumad ur so bad at this dude stop trolling im gonna report you"
I think it has to do with geekiness is now more socially acceptible than ever before. Therefore quoting mematic phrases from the Internet is now a "cool" thing to do. These phrases are showing their faces more commonly in public and over time simply become overused.
As for just being a jerk and pointing out people's flaws, humans have done this for millenia and on the Internet it doesn't change.
For the record I just pretty much laugh at anyone who says lolumad.