This entire case is a shining example of why "Muh good guy with a gun" isn't appropriate in a real life, chaotic situation.
Gaige thought he was being a good guy with a gun, and it's possible Huber thought he was being a good guy with a skateboard, but neither of them had the drone video, analyzed it together, evaluated the justification for Rittenhouse's action, and acted accordingly; they were caught up in a mob that convinced them Rittenhouse was an active shooter and a threat to the crowd, and acted on that assumption. If anything, they were the vigilantes in this scenario.
I'm not saying Gaige didn't have good intentions, or even should be charged with attempted murder or anything like that, or that Rittenhouse didn't act a fool to try and LARP first responder, or that open carried firearms in a riot is at all not a recipe for disaster.