Whichever view angle you prefer, the WALKWAY is too thin to support that many people.
Ffu has a good report on walkway failures (ie florida pedestrian walkway failure).
The walkway above would have to be made of steal to be that size and RELIABLY hold that many people. Unfortunately it appears to be "concrete and rebar" cheap constrution with allot of lies in the paperwork about capability.
MORESO - the area was not designed for protests. It was designed for lighter foot traffic. It isn't supposed to be fully loaded with rambunctious people "rocking it".