There is no evidence I've seen to date that Rosenbaum or Huber were committing any crimes that day, looting, arson, or otherwise.
Somebody fired a gunshot during the first confrontation. Rittenhouse heard it. To date, though, I haven't seen it established who that person was, or what they were aiming at, or even if it was a shot fired at Rittenhouse, that missed, or into the air, or was taking place in some entirely different situation/confrontation.
Grosskreutz, who was only injured, AFAIK, was the only one with a (hand)gun. He pointed it at Rittenhouse. He did not fire it (AFAIK). But he was shot and wounded. BTW, I could see
that being considered self defense.
Again, AFAIK, Rosenbaum had no weapons, and Huber had his skateboard, which he may have used as a weapon, but I don't think is normally considered one, and probably was not brought to the protests to be used as one.
Yes, both Rosenbaum and Huber struggled with Rittenhouse to disarm him, because he was pointing a heavy rifle at them. They feared for their lives. Weren't they standing their ground, trying to disarm someone who presented a lethal threat to themselves? I repeat: before struggling with Rittenhouse, neither had been nor was committing any crimes, and they struggled with him to take away a lethal danger to themselves.
So Balch says Rosenbaum earlier threatened to kill them. He might be telling the truth or he might not. Were there independent witnesses to that statement? Zimmerman claims when (supposedly) Trayvon jumped out and ambushed him he screamed "I will kill you mutha-f!"
Of course he would say that, dead Trayvon can't contradict him. I can see why he might lie. And I will leave it at that. The only thing I will say is Rosenbaum had no gun or anything else with which to kill them, so I guess he was threatening use of a lethal karate chop.