However, there are different situations. For example, I imagine this person is not very surprised or upset to be called "dyke" in a verbal altercation. That is different from sitting in a quiet courtroom, knowing it is being filmed, watching a popular video where your gender identity and expression is repeatedly insulted.
Let's say the officer was black, the defendant was white, and made a video with lots of racist stereotypes. Would we think that was funny and cool? Would we be surprised if the black man had a breakdown in the courtroom watching it? We wouldn't even be having this conversation.
By all means, call cops pigs, liars, thieves, idiots. If you want to be racist, sexist, or call them pedophiles, I'll defend your right to do so but not be as sympathetic.
Otherwise we're just the hypocritical liberals as the right wingers accuse...
This is very common in the US? Common enough to be a minor plot point in a current cop show (Cross), which is to say the audience will be familiar with the material. Also explored in e.g. True Detective. No, the Black cop does not get to break down in court while being racially taunted. Either on TV or real life. This is expected by all to be a part of doing his job.