UFC is not a duel in the traditional sense, nor is it 'violent' in the same way a war or aggravated assault is 'violent'. It's a technical sport (well UFC is a league of MMA fighters, where MMA is the sport) with well-defined rules designed to minimize damage to participants. Saying that the popularity of MMA shows that our society is getting more violent doesn't make sense, on the contrary - it's proof that we are able to channel primary urges to measure ourselves with our fellow humans in controlled and structured ways.
As for your link, an anecdote does not data make. If you want to argue that our society is getting more violent you need to prove that the amount of violent episodes now is higher than in the past, not that there happen violent events now. And as a matter of fact, overall in most of the Western world, the amount of violent crimes has been on a steady decline for the last 50 years at least (the amount of other crimes has gone down too, by the way).
As for your link, an anecdote does not data make. If you want to argue that our society is getting more violent you need to prove that the amount of violent episodes now is higher than in the past, not that there happen violent events now. And as a matter of fact, overall in most of the Western world, the amount of violent crimes has been on a steady decline for the last 50 years at least (the amount of other crimes has gone down too, by the way).