I think what we have to be very clear about is that while most armed groups will use rape as a weapon of war very few will explicitly set up human trafficking supply lines, slave markets etc in an organised way with a supporting bureaucracy. They saw themselves as a state, they behaved as a state, sharing resource taking responsibility for utilities etc.
Also I would be a bit careful about making assumptions about what muslims think,. I actually live in the middle east and the country I’m in quite a few of the older lot are very wary of Palestinians (some outright hate them (not so much the younger lot) and some think Assad is right becuase he’s fighting terrorists. Many are quite xenophobic towards muslims of other nationalities etc. There also people with completely opposing views. To be honest, some of it was a total surprise to me and forced me to re-evaluate and not make so many assumptions.
The problem with the whole “what the muslim world thinks” stuff is that it’s totally true that imperialism and recent wars had a deep and lasting impact on middle east but they have their own history too. Seeing the “muslim world” purely through the lens of how they interact with the west is a very narrow view of peoples with their own history, culture, faiths and conflicts that stretch far back.
Plus I come from a heritage where my people have been colonised. Have I taken sex slaves or tried to blow anyone up - have I fuck. It’s one thing to not want military adventurous from the west its quite another thing to act like it makes buying and raping other human beings an actual slave trade (like the one we criticise the west for) not their fault.
Theres a lot of “if we hadn’t done this they wouldn’t have done this” brown people do have actual agency y’know. Loads of practices such as FGM, sutti, purdah, slavery were around a long time before the west arrived.