You asked if these community districts are the primary political subdivision of each borough. I think the report makes that clear; none of the other kinds of districts you listed can make such claims about their stature within city government. These aren’t merely divisions on a city department’s org chart, and at least in theory they have a wide remit.
Is your expectation that any boundary=administrative within a city needs to have a dedicated authority with executive or legislative powers? That seems like an unnecessarily high bar to clear for something so local. In my opinion, the existence of these boards goes beyond what’s needed for an administrative boundary, regardless of its advisory nature. A city is within its right to divide itself into political boundaries. In fact, there may not even be any precedent for a U.S. city to legally devolve its home rule even further, so you’re basically saying there should be no admin_level=9/10 anywhere in the country.
A better sniff test would be whether the authorities intend the public to be aware of these political boundaries even when they aren’t interacting with a specific government agency – that is, not just when reporting a crime at the police precinct, voting in a council election, or applying for a taxi medallion. A colorful schoolyard mural of Queens community districts may not have the gravitas of the signposted boundaries of Maine’s (government-less) townships, but it still suggests that these boundaries are usable as administrative boundaries, as do all the community district maps that the city puts out for residents’ information.
By this standard, I would favor retaining all the barrios in Puerto Rico as boundary=administrative, even though barrio government is nonexistent, but I would also favor retagging Baltimore County’s legal subdivisions as boundary=place or named landuse=residential areas, because they’re only “governed” by private HOAs.
This has been the case for quite some time. If you generally want hyperlocal political boundaries in your application but find New York’s community districts too small, insignificant, or weird for the gameplay you want, we could add border_type=community_district to help you filter them out specifically.