Take Tumblr for example - they sold to Yahoo. Verizon bought Yahoo. If I was an engineer at Tumblr I'd be pissed that an evil monopoly like Verizon that's fighting against net neutrality is suddenly using my code.
I'm more humble now than I was in my 20s, and I don't think my code is anything special, but I still fear that the private company I work for will sell everything I built to someone I consider evil. If I have no control and no equity I'm going to act like a mercenary... I'll do the job efficiently and according to specifications, but they don't get anything extra. If they have an idea and have me build something that gets them rich that's great - but I'm not going to be like the guy who built GMail on the side at Google... I just do the job they tell me.