> He was fired for being political at work. Don't be political at work.

Well, more specifically, I think he was fired for being political in a way that caught outside attention and caused bad PR. Plenty of people are political at work, whether they be work politics or otherwise. This is a "You made the company have to weigh in on something that is way over your pay grade, and that's not something we're going to take a chance happening again with you." Executives and boards don't like when they have to stop what they're doing and put out a PR fire started by a low rank employee, whether that employee expected that outcome or not. That the firing of the employee causing problems at the executive level coincides with a way to combat the PR just makes the decision all that much easier.