Wow, the exact same thing happened at my work about fifteen years ago. 'You cunt' screamed at an innocent receptionist because she called a man 'sir'. Evidently, in a busy lobby, the receptionist was supposed to instantly recognise him as a woman because he'd grown his hair long.
He was super litigious and tried to sue us when we went to exclude him from the building. Gender discrimination, you see. Also disability discrimination because he had PTSD and is therefore allowed to scream at people.