*USC draws backlash for canceling valedictorian’s speech due to support for Palestine.*

Whether she was actually going to talk about that in her canceled speech is unknown, but supposing she was, "support for Palestine" is a rather broad category. There are many different views that qualify, and most of them are not threatening anyone.

The concern for "security" that the university claimed was a bogus excuse — in effect, "We are gagging you for your own safety."