It's a purposeful catch-22 that the anarchists have successfully put the police officers in.
It leaves the officers with two choices.
1. Don't get involved
2. Get their ass handed to them if they get involved
The anarchists are fine with either choice. As a bonus, if #2 comes to fruition, the lethal force option will undoubtedly have to be considered and that would be the biggest win out of all options for these lunatics. These people are sick and this is a play towards revolution. These tactics are straight out of communist manifestos. If you don't believe that, read one.