Is there a particular book you have in mind that “Park Slope progressives” would find too objectionable for libraries to loan out?
[1]https://antelopehillpublishing.com/product/the-transgender-i...
There appear to be three listed copies worldwide.
https://www.worldcat.org/title/transgender-industrial-comple...
Like?
I can think of plenty, but not anything that would be outright banned from the New York library system.
To be fair, it's not explicitly banned AFAIK, and it's a bit of a niche book (but it's famous among the respective hobbyists).
Also, to their credit, I looked up a bunch of other must-not-be-named titles you usually don't find in public libraries, and they did have most of them.
[1]: https://www.amazon.com/Practical-Lock-Picking-Physical-Penet...
[1]: https://www.bklynlibrary.org/search?search=practical+lock+pi...