You are right of course. Where I live, in very far-away Canada, a corporation can't fire an individual for pretty much anything they did on their own time. Commit a crime on the job: yes, they can fire you. Commit a crime after the shift ends: they can't touch you.

I was aghast when I read about that lady who worked for an investment bank get fired for being a shithead while walking her dog in Central Park, on her own time obviously. Just imagine having that kind of power over CUSTOMERS. It's utter insanity.