Go to your company's competitor, and apply

that seems like an unlawful dismissal check the labor laws where you live

I would sue not that I'd want to work there

Sorry, take this as a real world lesson. The boss does not want to hear a critique of their behavior or how they do their job. Just keep that stuff inside unless they specifically ask for it - and even in that case go very carefully. I am not saying your supervisor was right or justified - Just that it’s really hard to fight authorities and bosses. If one excuse for firing you won’t stick they will use another... Most times it’s not worth the legal fees to fight an unfair termination. And many US states have laws saying that they don’t even need a reason to fire an employee. You have every right to refuse to do something illegal and as long as you keep it to that case you might be safe. But it’s not wise to point out that supervisor is doing something wrong unless you have a relationship to your supervisor’s boss that will cause them to listen to you. But bear in mind that your supervisor can lie and probably knows his boss better than you do. Welcome to capitalism in the USA. You aren’t going to change it, but if you understand it, you are less likely to get hurt.

"I humbly apologize. It was a matter of perception - he wasn't showing any signs of being superior at the time."