From what I’ve read Genghis Khan was a pretty fair guy at first but once he encountered Islamic opposition their brutality turned him into an avenging demon. It’s too bad he had problems with his command chain back home. He had to turn back from Bagdad. If not for that he would have sacked Mecca and any idea they had “divine protection” would have been crushed. Perhaps God kept that rotten cult around for a good reason latter on.
In this first initial period when Khan had a curiosity...he sent a number of people to act as traders and observers. They were all executed, in a pretty harsh fashion. You can draw your own conclusions, but he had zero sympathy for anyone from the region from that point on.
The interesting thing here, which few ever realize....as the Crusades were coming to an end, and the region was going to expand out with Muslim control...along came Khan....who literally set the whole region back by 300 years.