Not quite sure what you're referring to here - Silicon Valley voted heavily against the current president. 68% margin the other way in Santa Clara county and 73% in San Mateo.
Some did, others didn't. That's how it normally goes; there were plenty of Romney, McCain, and Bush voters in tech. The only reason it went differently during the last Trump presidency is that he went out of his way to antagonize tech leaders while promising to end the H1B program their businesses heavily rely on.