If a 90 year old person with a cane threw a sandwich at a 6'3" 250 pound professional athelete, everyone would check if the 90 year old was ok. Vice versa, and there would be a lot of anger and an arrest.
The state's law enforcement, with weapons, training, ballistic vests and helmets, etc. is the ultimate power. You can't do bodily injury to them, but minor contact and sandwiches are usually not taken seriously.
People ask the same question about situations where there is discrimination - is it a double-standard? They are forgetting about relative power: If someone is in a group that is threatened - e.g., an Auburn fan in a large crowd of rowdy, drunk Alabama fans (Auburn and Alabama are arch-rivals) - then an Alabama fan saying something threatening is a real threat, a real danger. If the Auburn fan says something threatening to the 100 Alabama fans around them, it doesn't represent anything; it's almost funny.
The equation is,
Threat x Power = DangerMy hypothesis is that people generally feel that police face little to no accountability and so there is a more serious double standard to contend with.
Though there could be a terminology difference between countries - maybe in America, assault requires intent to injure? In other countries it can be any unwanted physical contact. Looks like that's called "battery" in America. So yea I probably meant battery.
To put a finer point on it, he was charged because the current administration wants to chill protest against their undemocratic (small 'd') and unlawful activities. In fact, that was the point of deploying ICE/National Guard/etc. to cities in the first place -- to sow fear and limit freedom of expression/assembly.