Equivocating speech and crime as both being "violence" (of similar class, deserving similar response) is a fallacy that lets people justify murder in response to disagreement as long as it's deemed serious enough.
Yes it's not violence, but it's not speech either. Donating money is performing material harm. That might be an unfortunate reality, but it's undeniable. It's a different thing from just saying something.
Also, you can absolutely be fired for just saying something and that's been the case forever. As a CEO, you are essentially marketing your company. Marketing it poorly and losing customers can, and will, get you fired - in every company, ever.
Really? Having an opinion endorsed by the mainstream doctrine of several world religions with billions of adherents is the same as robbing a bank?
That being said, I disagree with Eich and it probably made sense for the org to let him go given how his views might impact public perception of Mozilla.