Sounds to me like you have a Hell of a discrimination lawsuit.
Get a lawyer BEFORE you get fired.
You might not have to work again after they fire you and they settle.
Work related lawsuit settlements are very small. You only hear about the very rare exceptions. Normal amount for a non minority lawsuit (even with extreme violations) is around 30 to 40k at most. Also, been there and done that. and my situation was outrageous.
Good luck in all these things. If you are willing to risk it I’d suggest you thank your boss for his advice and ask him/her to put it in writing. You should keep a log book of cautions and incidents conducted by others that did not lead to cautions. If your boss has a boss that is how you take things up the ladder or to a lawyer.
No grounds for a lawsuit unless he owns the place.