Have you considered what would happen if an active shooter, consider one that’s pro-Israel, showed up in that crowd and they didn’t have a sniper?
Tell me you wouldn’t be over here screaming “ACAB” when the cops are unable to get to the shooter (and have to risk firing through a crowd or do nothing) because there are hundreds of college students between where the cops are standing and where the active shooter is.
Having a sniper on the roof is in no way similar to a tank running someone over in the street. There is no practical application for a tank vs a civilian population. There is 100% a valid reason to use a highly skilled marksman to increase the odds that if something bad does happen, it’s stopped quickly, and you can get EMTs to the injured parties.
Your position is offensively wrong.
EDIT: Minor edit to remove a swear and switch to textual emphasis.