@LouisIngenthron Again, we're not disagreeing in principle. We both agree that it's legit for libraries to make choices on the basis of some nonideological mix of popularity, notability, value-as-a-reference, etc.

I'd put to you, though, that the fact that I could bring up the Turner Diaries and pretty much all of my interlocutors know what I am talking about suggests that it meets a notability threshold that, absent other concerns, would be sufficient for many libraries to carry it.