There are a lot of moving parts involved with this situation, and it seems the discussion has drifted away from the point of the OP. No one seems to take into account that the BLM/Antifa rioters shouldn't have been there in the first place, and the Gov of WI let the riots and looting go on too long without calling in the National Guard to stop them by whatever means necessary. It stands to reason that after all the damage and destruction that has previously been done by these domestic terrorists with little to no resistance in Seattle and Portland, some sensible Americans would decide enough is enough and take matters into their own hands to protect their lives and property.
That being said, it's not surprising that a 17 year-old kid whose ability to make sensible judgements is still in the development stage would decide to get involved in the Kenosha mess. Granted, it was a stupid decision but keep in mind there may be some mental issues with him that factor in as well. Wanting to get in the middle of a domestic terror attack by armed thugs is evidence of that. However, he had a right to be there and speculating what he was thinking or what his motivations were is pointless and irrelevant.
So in doing so, he violated some gun laws and likely some other statutes as well but the idea of sending him away for the rest of his life for "Thought Crimes", 1st degree murder, etc is totally unjustified. Hopefully his attorneys will handle this well and put the Thought Police back in their bottle.