That reddit post has links to all the video of the situation. It got gilded five times over. In the larger thread there is another guy who does the same thing this dude did which also got gilded multiple times, except the dude that made that post makes it a point to say he hates Trump supporters, is a hardcore leftist, and yet that the kids didn't do anything. You can interpret w/e you want from it I guess, but the video is all there and it completely explains the situation. There are links to the full, unedited video if you take two seconds to look. What more exactly do you need?
Color me not surprised that when presented with clear evidence that the media manipulated the video clips they showed to rile the mouth-breathers up, said people in this thread doubled down on not admitting they got played.
It's obvious that a) the kids were minding their own business until some Black Israelites started saying awful shit to them b) the kids responded by laughing and doing school chants c) Native American protestors inserted themselves into the situation and also provoked the kids and acted kind of shitty to them d) kids again responded not in a hostile way but playing along and goofing off. Are they assholes for being Trump supporters and wearing those dumbass hats? Sure. Did they start and/or escalate this situation and deserve to be made out to be harassing the poor, innocent Native American vet and likened to white kids harassing blacks from the civil rights era? No. That would be patently obvious to anyone with common sense, but we live in the hyperbolic age of Trump, so I guess not.