Who are the men on top of the building?

They're snipers poised to kill for capital

No way to know, really. Perhaps Tesla is concerned the protest might get too rowdy. They might be paramedics perched atop the building, watching like hawks, ready to deliver medical care up to a range of hundreds of yards at thousands of feet per second.

Nazis

Probably some bootlickers

Probably some middle manager of the security team who thinks it's his job to keep an eye on things. No real concrete goal, just something that feels like what he should be doing.

Just some goons ready to make sure history rhymes.

Basic surveillance, possibly enhanced with cameras and wifi.