No, I haven't used the "logic" you mention. The problem with the investigation into Flynn wasn't his statements. It was and is that because there was no basis for an investigation, Flynn's statements, whether true or false, aren't material. What elements within the FBI may have done with regard to Flynn, while a serious matter, is necessarily a separate matter. The prosecution's revealed behavior was sufficient to undermine the case. Van Grack may have to answer for prosecutorial misconduct.
You're assuming bad police behavior. I haven't seen anything seriously wrong with police behavior, but I'll take you at your word that there have been some incidents. If you are protesting peacefully and people around you start rioting and looting, .my advice is to get the **** outta there. Nothing good happens in a riot, but put the blame whete it rightfully resides - with the rioters, looters, and arsonists.
But to the point, this wasn't happening a week ago. If some police don't have names on their uniforms, it's likely there just wasn't sufficient time to get that done.