Honestly, this depends on a lot of things. If I was the NCO or Officer in charge of doling out punishment, I have to tell you....you're probably already considered guilty - because you started the fight. As an officer, I've been in these situations before. And unfortunately, in that position, sometimes your personal opinions don't matter. What really matters is the perception of the rest of the unit and the rules and regs. It WOULD NOT look very good if one of my troops started a fight with a guy and then never got any punishment out of it. Because that is all that people see - not the build up.
Now, a few other things come into consideration. You said that people know about and someone talked to him. WHO knows and WHO talked to him? Was this just some guy or someone in yours or his chain of command. That makes a big difference. Because I have to tell you, if I heard about someone treating one of my troops like this, I'd be in the other dude's face within 5 minutes. And that would be immediately after I had talked to his platoon leader or company commander. If you have brought this to the attention of your chain of command before it had escalated, that will have a BIG effect. Even if you hadn't before, you need to go to your chain immediately. Fire Team Leader, Platoon Sergeant, FSG, whoever you can.....but start telling you chain what REALLY happened before a decision on a punishment is made without your information. A lot of times the decision is made before you ever get in the office. It sucks.....but that's the military.
So to be perfectly blunt.....as a normal person/civilian, no, I don't think that you should get punished. As an Officer, yes, you should probably get punished. But if I knew that he had been doing this in advance, it would make the punishment a lot less harsh.
I actually had a troop in this EXACT same position, if you want the whole story and how we dealt with it, PM me.