They tell us over and over again that we should have no expectation of privacy or not being filmed in public. Well, IMO they should not have any expectation of privacy or not being filmed when on private property and conducting the work _that we pay for_. They work for us.
That is, in fact, what the law says and what the courts have agreed with multiple times.
and I imagine that if the INVERSE of this case had come up, the police suing for defamation would have been protected by qualified immunity so no lawsuit would have been possible.
The police being able to leverage civil law against citizens to control their behavior in ways that citizens cannot leverage against cannot to comment on the abuse of power is entirely unacceptable no matter what our laws and judiciary chose to allow.
That is not just your opinion, that is the opinion of multiple United States Court of Appeals circuits in many many cases, and by its declining to overturn these cases, that is also the opinion of the United States Supreme Court. The United States is a common law country, so really what that means is that your opinion is actually not an opinion at all; you have simply stated the established law of the land.