National Journal has an article about techies in Silicon Valley, and the Bay Area more generally, who are conservative but in the closet politically. Most feel if their right-leaning politics were known the knowledge would harm their career, their firm, or both.
I relate to their experience. I spent 33 years in academia, most of it as a neocon who voted GOP nearly exclusively. Even in my university's Business school faculty, conservative politics were somewhat uncommon and they are certainly rare across campus. I kept my opinions largely to myself, although a couple of friends knew I was no liberal.