I do understand why people would have a visceral reaction to the feeling that a librarian wasn't a "reader" - that how could we support people in finding a love of reading if we are not lovers of reading ourselves, and that is generally a notion I would agree with (for what it's worth, I have read Wolf Hall, and really enjoyed it, but I do like historical fiction generally. Not everyone does, and that's ok!). But I do think there is an interesting conversation to be had here (perhaps poorly prompted by the OPs post, which does come across as snobbery) about what reading is valuable, what literature is valuable, and what makes people actually enjoy reading.
I want kids to love reading, to value it as a pastime and choose it over dicking about on their phone. If they are someone with a short attention span, entrenched in a habit of going on social media to relax, if all I can recommend them is "classic" literature or weighty tomes then they're going to come away thinking the library is not for them. And in a diverse school, there are plenty of children for whom the Tudors might be something they can't connect with, but stories from their culture or home country would be much more engaging and interesting, enabling them to see themselves more in what they read. And yes, of course there were still voracious readers and who I wouldn't really need to work at finding extra reading for - they would often suggest books to me!
Overall I think the message from a librarian shouldn't be one of venerating a particular canon above anything else, and that all reading is valuable, not just someone reading what you think is worthwhile.