Most people don't want to read most earnestly banned books. It's a very notorious book though, it would probably garner more attention than many uncontroversial books in the long tail of most library collections, which are neither loved nor hated, notorious nor famous.
But a lot of the people interested in reading it would probably have right wing inclinations, and the average librarian doesn't want to support that sort of thing (not least because the nazis themselves were big on book burning..)
I would not be surprised to learn that modern librarians have permanently destroyed and lost more books in the past five years than the Nazis did in their entire reign.
Most of it is less nakedly ideological - its presented as necessary due to the collection size - but certainly not all of it. There are many famous cases if you Google it, and it is happening quietly all the time on the local scale. Talk to your local librarian - I was shocked to learn their methodology.
The Anarchist’s cookbook is on Amazon but not my local library for example.