The campus is open twenty four hours a day. If you went to South Bend right now you could walk anywhere you wanted on the grounds, unimpeded.
At the time in question, supporters of Obama were allowed to continue to do so, with signs or whatever.
Anti-Obama protesters were treated differently, based on nothing more than the content of their speech.
Are you saying that if tomorrow Notre Dame University suddenly started acting as if it were Catholic, the university would not be able to prevent a gay pride demonstration or a pro-abortion demonstration on campus?
If NDU is private property, then NDU can discriminate against whatever viewpoint NDU wishes.
In this context, the 1st Amendment does not apply to private property owners.
Your proper outrage at NDU’s choices seems to blind you to sound legal reasoning and a sound understanding of the Constitutional right of private property owners to control the speech activities that occur on their own private property.