Well, and go one further: if a common employee does hold an unpopular opinion and they publicize it widely, think how long they'll last at the company anyway.

Take a totally fictional example, a product manager at Intel who, on the weekends, has been leading neo-nazi marches and getting on the news. The reporters ask him, "what do you do to pay for all these flags and banners and tattoos?" "Oh, I work at Intel during the week. I'm a product manager in the networking hardware division."

Think how many weekends they'd give out that interview answer before Intel let them go for whatever reason.