University libraries of course might be a good exception to this rule. But your local public library should be a way to make reading accessible to the average middle to lower class family. And that means providing the materials they want to read - not what you think they should.
It's always going to be a balance for librarians. They don't get to operate in ivory towers disconnected from those local taxpayers whom fund them.
How dare librarians... give the people the books they want to read???