Secret Police Are Tyranny

That is demonstrably incorrect. In every photo I've seen, the police have a POLICE patch on their plate carriers and unit/agency patches on their sleeves. Further, many have unique callsign patches on their uniforms. Admittedly their colors are subdued, but that goes along with the camouflage.

There are multiple problems with what has been going on in Portland, but allegations that the police were unidentifiable isn't one of them. In terms of uniquely identifying officers, there's no law requiring that (it's up to individual agency policy), nor is there any rule to inform someone why they are being arrested. It's legally enough for them to say, perhaps in the van, "I'm a federal agent and you are under arrest."

Not that it matters, but I have issue with the police wearing military uniforms without clear and obvious need (e.g. police snipers/observers in a rural area). It should be very obvious whether a person is a police officer or a soldier, especially for those who don't speak good english or come from outside the United States.