If this were any other website, I'd suggest simply requiring a Facebook or twitter account to log in. Worked for Gawker et al, but it won't fly with this demographic.
So just charge people $1 to activate their account. It'll reduce the shite, and 99% of the commenters won't care. What happens to the edge-cases of people who don't have a credit card is an open question, but I suggest validating them some other way (solve a problem in Lisp perhaps).
It just restricts the site to those people who can/will pay.
There are plenty of people who'll gladly pay for the privilege of trolling or posting garbage. And the more they pay the more entitled they feel to post whatever the hell they want.