Saying "screw you" really isn't even seen as that offensive anymore. It's kind of become seen as a norm in society and most people don't think much of it. Just because one's a deputy doesn't mean he's forced to talk like he's actually of any significant importance with super clean language. I think you're blowing this out of porportion a bit. Now if he were to actually curse at you or something it would be understandable, but I doubt you'll see much punishment to one who simply said "screw you".