How exactly is an individual supposed to determine which cops will be good and which will abuse their power?
Just as we can't make a general statement that all cops are definitely bad, you can't make a general statement that all cops in any particular country or town will be good.
From a basic risk management viewpoint, it doesn't make sense for anyone to accept the risk that any given cop won't abuse their position, even if we were willing to accept that very few would actually do so.
Cops have an extremely privileged status in society and the amount of damage that a bad one can do to an individual - on purpose or even by accident - is incalculable, including setting up an innocent person for capital punishment as we're seeing unfold in Missouri right now.
Google is an enormous company which operates flatter than you'd expect for an organization of its size. It's entirely possible that someone from Google was involved in organizing this (i.e. booking the venue) without having buy-in from leadership. Once leadership became aware after being asked about it, they may have shut the whole thing down because they knew the optics would be bad.