I’ve asked librarians a full range of tech questions about what works, what’s blocked, what’s allowed.. they /never/ have a clue because of outsourcing. Their guess is as good as mine. In the 90s, I would say you are spot on. Librarians should have answers. Things have evolved to where the policy is decided non-transparently, it’s outsourced to an unreachable company, and librarians are simply as uninformed as the public. Trial and error. If you read the AUPs it never says Tor is banned at libraries, for example, but they simply block it. Experimentation is the way people get answers in my area.
So knowing that librarians don’t have deep tech info, or even basic tech info, and that they also cannot escalate questions, talking to them is really where time is wasted.