I'm pro Israel and very anti Hamas but I have a different view on this.

IMO:

1) Young people post many things and it's hard to know if the bad posts are one-offs or part of a clear pattern of a belief system. In the very brief amount of time I've spent on this situation, it's not really clear to me that they were more than one-offs, so in full disclosure, the rest of my thinking is based on assuming they were one-offs. In other words, I'm not convinced she's a "raging antisemite" any more than I'm convinced that someone who says one bad thing about a minority is a "raging racist."

2) USC should not select a vile antisemite (or racist) as valedictorian. A post or two expressing sympathy with Palestinians does not rise to the level of a vile antisemite. Perhaps what she actually said is just as bad as your example of "lynch all blacks" but it didn't seem to me to be the same. If it was, then she should have been removed as valedictorian.

3) We had no idea what her valedictorian speech would have been about. Her posts sympathetic to Hamas didn't necessarily mean she was going to say anything about that during the speech. USC would be within their rights to restrict her from including any political messaging. If she violated any agreement, then she can face the consequences, but cancelling the speech just in case is just wrong.

4) USC set a terrible precedent cancelling the speech but allowing her to remain as valedictorian. Either remove her as valedictorian or allow the speech. Anything else is splitting the baby.

5) Using "safety" to stifle free speech is a loss for freedom for all of us regardless of who's speech is being stifled. We should support free speech for all.