According to this law professor, OU chose breaking the law over bad publicity.

Glenn Reynolds writes in USA Today:

OU broke the law to avoid bad press: Column

It has been a bad spell for the University of Oklahoma. First, some members of the Sigma Alpha Epsilon fraternity were videotaped singing a racist song on a bus, and a video went public. Then OU President David Boren kicked the fraternity off campus and summarily expelled two of the fraternity members.

You may think it’s unfair for me to treat these two incidents as comparable, and if you do think that you’re right: The difference is that David Boren broke the law, while the fraternity brothers merely behaved badly.

As a state institution, the University of Oklahoma is constrained by the Constitution. Among other things, that means that it must respect the free speech guarantees contained in the First Amendment, even if that speech is repugnant. Just because the university doesn’t like what students say, thinks it’s hateful, or worries that it will produce an unpleasant atmosphere on campus, doesn’t grant it the authority to punish people for speaking. One would think that Boren — a former U.S. senator who took an oath to uphold the Constitution when he was sworn into office — would know better. Apparently not.

UCLA law professor Eugene Volokh has a column in the Washington Post titled, “No, it’s not constitutional for the University of Oklahoma to expel students for racist speech.” Volokh comments: “First, racist speech is constitutionally protected, just as is expression of other contemptible ideas; and universities may not discipline students based on their speech. That has been the unanimous view of courts that have considered campus speech codes and other campus speech restrictions. … The same, of course, is true for fraternity speech, racist or otherwise.”