The guy you're replying to states flat out that (he believes) the police are correct, and the Portland DA is refusing to press charges for political reasons unrelated to whether any crime actually took place.

In effect, he's arguing that rioting has been decriminalised in Portland without any popular vote and without any explicit decision ever having been made. If that's true it's unsurprising the police keep arresting people and they keep being released. The issue there wouldn't be the police. If Portland wants riots to be legal when the rioters support leftist causes, they should explicitly adjust the local laws to allow it.

That said, the link they provide states the guy was released "on own recognizance" which basically means he promised to turn up in court at a future date, albeit with no bail money paid. So it doesn't say charges were dropped.