The cop was wrong for telling the guy to " off", as cops, you need to be better than these types of people. Also cops are human too and mistakes happen. We also haven't seen the unedited version
There
should be a law against filming government buildings such as Police stations, Military bases etc - something more substantial than having to believe the person is a terrorist.
Coming out of police stations you can have CHIS, victims of crime, identifying police personal vehicles etc. For military bases, you could be filming SF personnel, or persons families.
Worse case, the person filming
could be a bad guy and carrying out hostile recon ie weak points, shift changeover timings etc. It a well known TTP for bad guys to carry out recon, trial runs etc.
All of the above, creates an extra risk, so why allow it?