I have friends that grew up in countries where the Muslims were a minority and socially separate from the rest of the society, and some of them have told me I was naive and clueless for pointing out that there are many societies that are culturally Muslim that are tolerant and relatively peaceful. I understand that their experience of Muslims was negative and understand the human tendency to make generalizations.
Personal experience is a terrible way to make judgements, except to the extent you learn that something you heard could not be true. This usually takes the form of learning that a generalization you have accepted is incorrect and that the world is more complicated than you thought. I found this article to be informative and with a perspective that makes sense to me..
Pundits claiming that ISIS is emblematic of Islam ignore the intellectual traditions at the heart of the religion