There must be more discrimination than that. Then wouldn't the library be full of porn and romance novels? The two largest volume of new publications per year.
Libraries are full of romance novels. If you’ve ever stood in line to check out a book you may have noticed how popular they are. I’m glad that people are reading, and don’t see a reason to pass judgement on the people reading them or pretend that libraries should be filled with the literary equivalent of broccoli.
By "largest volume", do you mean number of distinct titles published, or number of copies sold? I think it's the former, which wouldn't translate into customer/patron demand.