David Boren was a Democratic politician before he became president of the university. I will be surprised if he doesn’t try to expel the students. It could lead to a lawsuit but he might figure that the students in question wouldn’t sue to get readmitted and instead would go somewhere else. After all, one of the football team’s recruits has changed his mind about attending OU. That’s more significant to OU than upholding the right of white students to say offensive things.
There isn’t much upside in suing.
OU isn’t much of a brand name for a degree so there isn’t much value to preserve.