Under normal conditions, American police can legally murder practically anyone for almost any reason. This is not hyperbole, the understanding of this fact was one of the reasons for the George Floyd uprising. Police regularly get away with murder unless there are mass uprisings. That is how America worked *before Trump*.
We have seen federal paramilitary execute multiple people in the street. Federal paramilitary were kidnaping people, putting black bags over the heads, interrogating them, and dropping them off in other places *in 2020*. The level of state terror has escalated wildly.
Against anyone but an officer, Song's response to the radical escalation of drawing a gun on non-violent protectors would be legally recognized as self-defense. Officers are trained to only draw a gun if they intend to shoot. The officer clearly intended to execute unarmed people. It is extremely unlikely the officer would have been charged even if someone had been killed.
But the criminalization of legitimate self-defense has been standard in the US for decades. What is new here is the ciriminalization and suppression of entirely non-violent protest.