Your implication is this is a case of a property owner restricting speech. The story doesn't indicate if the junior college is private, so, I googled the name of the college, and it's part of the California Community Colleges System. The property owner is the State of California that's trying (successfully) to restrict speech. I dunno, seems worth screaming about.
More broadly, my point was really about businesses and restaurants. If a pizza place were to hang a sign that said "No Spanish allowed", I would have no problem with it -- and I think the Constitution would have no problem with it. Sure, it might be a stupid business decision, and a lot of people would freak out, but if a restaurants wants to restrict my speech, I would shrug and move along.
I just think it's worth pointing out that the Constitution limits the federal government: not us. In this particular case, if the junior college is a (state) government institution, then I guess I see that they did a bad thing.