I think many people don't realize that service members swear an oath to defend the U.S. Constitution. While they also swear to obey the orders of the president and their superior officers, this is a conditional. They are NOT required to follow any order that is illegal or violates the Constitution.

What is the context of this? It's disturbing if masked men are just assaulting people for no reason other than protesting, while cops watch.

Perhaps, but with a much smaller grain of salt because there is a lot of evidence to support it. It's fashionable on Youtube currently to make anti-establishment videos since they get more clicks. But many seem to forget or overlook the evidence.