It's not any different, it's the same in the fact that niether comment should be racist. It's just that the victim of the insult would take it that way. You are simply stating a fact that you are black, the insult is the piece of shit part. You think a cop would care if you were like HEY! YOU'RE A COP! COP! OMG YOUR SUCH A COP!. No cause he chooses not to take your comments as "racist" even though that wouldn't be a racist situation, more like jobist.