> This also assumes that library was used in a way that counts as derivative work, which isn't always the case.
That's something a court would have to decide.
Whenever the AGPL comes up, people start arguing that in their opinion it doesn't cover certain things and therefore criticism of the license is fear mongering, but this misses the point that even if there is room to argue for that position, no company is going to want to touch AGPL software when the situation is ambiguous, since that creates a lot of risk, so that ambiguity is itself a fatal flaw of the AGPL license.