Some thoughts on this:
Generalization is probably human, it dates back to when people were in tribes, and lived their lives pretty much by the rule of 'our tribe' vs 'other tribes'. It has caused a lot of problems nowadays, because the human instinct due to this is to assume that the differences of other people, say, of blacks vs whites, are somehow both purposeful and malevolent. Obviously this is nonsense, if you think it through, a person cannot control the color of their skin, nor does their skin color mean they are malevolent, but most people don't think.
As for being caught up in minutae: There are people who think this way, this is how some autistics think. Being too autistic is not very functional, but it's actually useful to a group of people as a whole to have a few *somewhat* autistic people around, as they see things that other people don't.
Regarding Muslims, I agree that not all Muslims are criminals, but there seem to be certain *types* of crimes which are committed nowadays, mostly by Muslims. This uniqueness of a particular crime to a particular culture is not an exclusively Muslim phenomena, there have been other crimes which have been unique to certain cultures. The sin of 'violent wasting' comes to mind. This was a fairly common sin in the middle ages in Europe, but is simply not done any more by anyone. At least, not in the particular form that it was done in Medieval Europe. This being the case, if you read about someone who committed the sin of being a 'violent waster', it would probably be a fairly safe assumption that the person was a medieval European, and when reading about certain other crimes, it is often a safe assumption that the perpetrator is from some other particular cultural group. Snake handlers (a dangerous, unpleasant, and often illegal religious practice) for instance, are all from a particular area of the south in the USA.
This being the case, there are also certain crimes (or acts which many people regard as crimes) which are committed mostly by Muslims, so when hearing about someone committing such a crime, it's a natural and safe assumption that the person who did so, was probably a Muslim.
In fact, the act in question doesn't even have to be a crime, there are many acts which are unique to particular cultures, particular places and times. If you hear about someone wearing a hat that looks like a wedge of cheese on their head, or calling a water fountain a 'bubbler', it's a pretty safe assumption that they are from Wisconsin. And if you hear about someone going outside and praying at certain times of the day, it's a pretty safe assumption that they are a Muslim.
.