In any case, the people saying this is pretty standard security for a large gathering of people are correct in it's regularity, but I'm not particularly convinced that they're correct in its efficacy as a practice. They're all visible enough that they can be seen by the student body, which is either bad planning or blatant intimidation, and obviously gives up their position immediately, which is bad since they're potentially a would-be ne'er-do-well's greatest threat. If anyone becomes embedded in the protesting crowd, they become much less effective, if anyone takes up a tactical position, they become much less effective. If anyone starts to try to instigate violence between the protestors and police, which would probably be what any bad actor would do since it has a pretty high chance of success, they're much reduced in their efficacy, or potentially even negative in their efficacy as it leads to an escalation of violence. If anyone has a bomb or does chemical attack, the sniper is probably too late.
Plus, from what I've seen of the other protests, the police already have a perimeter set up on the ground keeping track of who enters and exits, which makes sense. Snipers would probably be better served as a part of that perimeter rather than surveying the inside of the protest, since they can cover a pretty large distance, you could turn them around pretty quickly, if they did need to fire on where the protestors are actually gathered, they can screen who's entering and exiting, and it's overall better optics. They could probably keep their position better concealed since there's not a huge crowd of people looking at that side of the building (if they even made any attempt to be concealed, which should be really the bare minimum).
This doesn't make any sense to me, even just as a kind of surface-level tactical decision. Maybe I'm missing something here, but this just seems like it's maybe stupidity, or intimidation or something else I can't think of.