From Steve Bainbridge: Speaking of GOP-leaning real estate barons, my guess - and it's just a guess - is that Donald Bren may have had a hand in this development. Bren gave $20 million to UC Irvine to finance the law school, which is to be named after him. His Forbes bio includes this comment: "Major Republican donor; a skiing buddy of Schwarzenegger." His campaign contributions are summarized here, mostly going to fairly conservative GOP candidates. IMHO, it his highly likely that Bren had a say in this. $20,000,000 donation gives him that privilege. The big mistake was not having him on the panel, which probably is the case, to approve the hiring in the first place.
Chemerinsky seems to have earned the professional respect of plenty of conservative lawyers. My only exposure to him has been on Hugh Hewitt. He reminds me of Noam Chomsky -- a substantial intellect that operates entirely in the service of liberal ideology. Like Chomsky, he is perversely interesting to listen to, but he should never be given real power.
My guess, like yours, is that Bren blew a gasket when he heard of the Chemerinsky appointment. If so, it would be hard to blame him.
Still, in the end I have to defer to Hewitt, John Eastman, and the academic lawyers I linked. They know their business better than I do, and they think that dumping Chemerinsky broke the rules.