Reframing this point: Some good books aren’t borrowed because they’re not discoverable, not because they’re boring.

The library is highlighting a few titles for increased visibility to ask, “would this pique a reader’s interest if they knew about it, or is this generally bad?”

Without this stage, the library would expunge more genuinely interesting titles.

I’ve always kinda felt the role of a library is for recall rather than precision

Without digressing into spy vs spy, I think deprecation warnings (shared with the customer base) are a good thing. It might not be a good thing for sales, but that's not a concern here either. A / B testing: if I see that, then what tells me WTF is going on? (You lose me here anyway, sales.)

Agree on the language lawyering, too. ;-)