super rich people people are going to support this because they realize that hatred of foreigners is the main thing standing between them and high levels of taxation. And they don’t want to pay taxes

The above is talking about the wealthy in general. For a discussion of Silicon Valley ideology specifically, see this talk by Bhante Sujato and for a discussion of Elon Musk’s specific flavor of psychopathy, listen to this conversation with Elon’s friend, Kara Swisher.