So weight (by itself) wasn’t a cause, but removing the concrete from the surface seems to have reduced platform stability. The platform became less rigid as the concrete deck got thinner, and so the platform shifted (or moved the pins off their support at one end of one platform.
Then, as soon as one end of one plate was free (or had wiggled too far - the construction crew said the entire deck was getting more and more mobile as the concrete got thinner) the other concrete decks were able to fall. Then, the whole structure came down because it was not locked in place at both ends of every deck section.
My opinion? The connections (of one deck platform) must have failed first, as you can tell because the individual decks and beams came down in complete pieces.
I was waiting for you to ping in.
Have you seen the surveillance video of the collapse?