It is unsurprising that Rittenhouse was cleared of the killings. The decision to prosecute him was dubious from the outset, as legal experts pointed out that a conviction was a long shot. It seems likely that the decision to prosecute was politically motivated, in an effort to temporarily placate the Black Lives Matter movement. But then they must also have anticipated that eventually it would reach this point, with Rittenhouse acquitted of those charged after a jury verdict.
It seems that leftists wanted him convicted of murder because they didn't like that he had come from out of town and brought a weapon. And also because they are dissatisfied with the state of gun laws in the country as a whole. However, learned people know that this is not the basis on which legal verdicts are decided, but by a consideration of facts and circumstances of events as presented in court. Experts pointed out that any jury was unlikely to convict on consideration of the evidence, as video evidence of all three shootings showed Rittenhouse firing only in response to being attacked. I considered it likely that Rittenhouse would be convicted on the firearms charge, until his defence counsel pointed out in court that his carrying the rifle was not against the law under which he was charged (although the media puzzlingly referred to this as his being let off on a 'technicality').
Rittenhouse is not a hero or a martyr, either. He should not have been there, and he especially should not have brought his gun. The same goes for the demonstrators he shot. There were plenty on both sides who flooded into the town looking for trouble, or looking to cause trouble.
There is a worrying trend in the US for people to bring their guns to demonstrations, or counter demonstrations. This is an intimidation tactic. They claim to be standing up for their Second Amendment rights, but really they are testing the limits of those rights, and the greater public's acceptance of them. If they continue the behaviour, with the consequences it brings (people being shot), then they may find that the broader public does not have much tolerance any more for their Second Amendment rights, and they might then be severely curtailed.