Why do you think it is OK make a massive generalization about a group of people like that? While I wasn't personally involved in Greek life during college, I have very good friends that were upstanding and principled members of fraternities that would certainly abhor the horrific and abusive behavior described in this article.
If you met a nice person today and later found out they were in a fraternity during college, would you immediately make judgements about their morals and conduct just based on that association?