So I got sent home early today...

[Husar]

I don't know TBH. Like I said, most people don't like him, and that's probably why. He's just a hostile person for no reason.

That's always a good sign to stop and rethink the situation from scratch.
It sounds like you just accept the situation as it is and don't think a lot about it, maybe he's just that way because nobody likes him and not the other way around?
Of course you're angry at him and what he did was wrong, but now's the time to rethink the situation.

Of course you may have already done so and still come to the conclusion that he is angry for no good reason, but consider that he gets punished for his aggression, you want to become a marine helicopter pilot, you have a goal. I don't know whether or not the marines are looking for brutal thugs but in case they're not I wouldn't risk that goal just to get back at some guy, imagine you hurt him a little more than you actually wanted or he falls the wrong way and then your whole future is that of a convicted felon or whatever it's called in the USA. Maybe this isn't likely but it surely has happened to people before and you should think about whether exacting revenge is worth risking that you ruin your life.
You can always do or not do, but you cannot undo what has been done.