No kidding. Interest is why a library would use their budget to purchase a book or not. The OP said nothing about the budget being used to purchase books being related to book bans, but that’s how you decided to incorrectly interpret it.
That does not say “they should be banned if there isn’t” or, even closer to your interpretation, if nobody checks it out or anything to do with budgets. There are two separate ideas presented, not perfectly, but still pretty obviously. “I’m not interested in it but someone else might be, it shouldn’t be banned” and “library budgets are low, they aren’t just buying books for no reason”.
No kidding. Interest is why a library would use their budget to purchase a book or not. The OP said nothing about the budget being used to purchase books being related to book bans, but that’s how you decided to incorrectly interpret it.
That does not say “they should be banned if there isn’t” or, even closer to your interpretation, if nobody checks it out or anything to do with budgets. There are two separate ideas presented, not perfectly, but still pretty obviously. “I’m not interested in it but someone else might be, it shouldn’t be banned” and “library budgets are low, they aren’t just buying books for no reason”.