What authority did they have to arrest him? He wasn’t an immigrant covered by a warrant, impeding whatever legitimate tasks they were doing, they chose to walk over to him, chose to initiate physical violence against the first person, chose to escalate when he tried to help the first person the agents assaulted, and the video showed that he was disarmed and subdued before they shot him.

Did you come to that conclusion after watching the videos, or just after reading statements from DHS?

ah, because the two choices the government agents have are "do nothing" and "mag dump a guy after you had 5-6 guys pepper spraying and beating him on the ground"