This is hysterical pish, Nox. ONE guy got beaten up and it was a massive fuck up that is going to cost the carrier millions.
Airlines that overbook, do so in the knowledge that the vast majority of the time they get their sums right, and as many people that they estimated wouldn't turn up for the flight, don't. People miss planes, forget flights, can't be arsed and have refundable tickets, or change plans last minute. It happens all the time and the airlines have finely tuned algorithms that they work to. On the occasions they get it wrong, more often than not, it's very easy to find people who'll fly an hour or two later, even a day, if offered compo, which is usually free tickets. On the occasions when people are involuntarily bumped they are pretty much never manhandled let alone brutalised.