Why is this a problem? Minor offenses are still offenses and they can often be very frustrating and problematic. They still deserve police attention where they constitute a violation of the law. Streamlining the process is a positive not negative, and the framing here just seems like these activist groups don’t want people to be held accountable.
The problem, as is always the case, is that "minor offenses" are not equitably enforced.
So if the local white kids are hanging out at the corner of the park smoking weed, no one cares. No one posts to Nextdoor. The police don't show up. But four young hispanic men walking through the same white neighborhood (to get to a job, say) will freak someone out and a busybody post to nextdoor will end up getting them stopped. Oh, and it turns out that one of them has weed in his pocket. There's your "minor offense". It's still an offense, right? It deserves police attention?
You're looking at this with a microscope. No one is saying don't enforce boring laws. People are saying do it fairly. Nattering busybodies on Nextdoor are the opposite of fair.
What is more fair than locals choosing which stuff is bothering them?
There may be noble outcomes from this, but there are also clearly negative ones. Once again, I'm not claiming it was ever ND's intent to do this. Just that in practice the design of the system enabled and tacitly encouraged these behaviors.