Well there is a difference between "American English" and "UK English", though too often, like you imply, it is used as a cover for ignorance of linguistic rules; such as the incredible display of abject silliness shown above.
I speak American English (laced with some USMC and USAF slang and occasionally lapsing into TropeSpeak), and it annoys my sister to no end, because she speaks British English and just can't stand the way Americans pronounce certain words.
On the other hand, both of us care about proper grammar, and I've sometimes even corrected native English speakers. While there's an opinion (mostly in Britain, from what I've gathered) that Americans don't care about grammar, in reality, the rules are only slightly more lax. No excuse for Illiteracy Communists like this guy.
Funny thing is, because I've learned English mostly by using it, while she is learning it in school, I'm better at conversation and "daily" English usage, while she is better at exams.