I think this is a better argument than merely talking about the content of the speech. That said the question is whether the punishment matches the severity of the crime. There was no due process here so we'll never know for sure.
There is rarely 'due process' when it comes to private institutions hiring or firing. Are you advocating for the government to intervene on behalf of citizens before allowing a company to make a financial decision?
This is an aside, but if you want my personal opinion, I wish workers had more power on their side in both hiring and firing (firing particularly). It need not take the form of the government intervening directly but regulation can't hurt.
