That's still a weird generalisation and pinpointing of muslims. There are billions of them, most of whom care little about minutiae in protestant christian canon. Coming from someone in a rather small and modern christian denomination that has spent a lot of time griefing about "paedo-baptism" I don't think it's actually about being impressed by 'knowledge of scripture'.
> most of whom care little about minutiae in protestant christian canon
Muslim and Christian scripture overlap by a large amount, it's not that they care about Christian canon, it's that they study the same books. Muslims have the stereotype that they are much more "serious" about their religion than Christians. It's not a negative thing.