Your final point essentially relies on us to believe that because we see evidence of ICE protesters doing things that range from mildly annoying to obstructive, ICE have carte blanche to execute citizens in the street should they be clever enough to manufacture the opportunity for themselves (like walking in front of a parked vehicle of a cooperative, but startled woman).
Your individual points about the technicalities of the actions of ICE being legal or illegal are imo immaterial to the above.
I’ve also seen lots of videos of extremely concerning behavior by ICE agents, like you have seen of protestors. The catch is one group of people are federal agents who can kill you without consequences, and the other group is a wide range of American citizens of varying degrees of intelligence, mental health, and passion that can’t be grouped together into a monolith to prove some point about whether they’re allowed to be executed in the streets.