Brendan Eich gave money to a cause that would have limited the rights of his employees. He actively chose to do that. If you're willing to publicly support a position you should not be surprised if it had ramifications. It doesn't matter if no one knew about whether or not he discriminated against employees, it's an appearance of impropriety and his actions outside of work led to a destabilisation of the company inside work. Same thing has happened numerous times to numerous people across any number of issues. It used to be that association with PoC could get you blacklisted. Then there was the Red scare. This has always been happening and most likely always will.