I think it's more about the culture of the campus itself than it is about a public or private school. If a school is conservative, public or private, most of the Greek chapters probably are too. At a party school,public or private, you're going to find a lot more craziness among the Greeks.
Also, I agree with SWTX. This is going the give the Greek haters that much more ammunition and will hurt chapters everywhere, expecially the organizations involved in the recent incidents.
Oh, and BTW, William and Mary is a public school!