MMA ... "It's nothing more than common street brawling with a fancy name". Like cricket is a guy waving a bat and trying to knock down a bunch of sticks.
It is a pretty brutal sport, no argument, but there are rules, violations, penalties, and objectives beyond doing personal injury with any means possible, which I believe is the intent of a street brawl.
For my money, rugby is probably just as violent and causes as many injuries.