I've only been to a couple DEFCONs, but thinking of DEFCON as a professional conference is a mistake.
To start off with, you are getting together a bunch of people who think it's fun, witty, clever, desirable and high art to assault other people's systems. The basic lack of respect that this represents bleeds over into all the other areas. And then you add in "Party in Los Vegan" and a lot of alcohol and you should not be surprised that there is a huge amount of misbehavior.
The really amazing thing is that despite this, there are a lot of good people and useful talks there.