You are correct that if you called a cop to have an ordinary person prosecuted for filming you in a park or at the side of a road that they would laugh at you and tell you to ignore it and move on.

The issue is if a pissed off cop doing something stupid would get his corrupt buddies to prosecute in this manner? Sure, rules for me but not for thee. It is seriously unbalanced and a form of corruption. Why a judge would accept that argument and convict for this reason is also something to condemn? Because they are a cop you recorded and nothing else.

It absolutely is in retaliation and because the judicial system gives different rules for police behavior than for us peons.