As your other posts have indicated, the image is not a "flag that the Balkan muslims flew during World War II." It is the insignia of the 13th Waffen-SS Division. There is clearly a difference between 21,000 Nazi soldiers and a region's Muslim population as a whole.
And my point is that those 21,000 troops plus the muslim recruits in other Nazi divisions plus the muslim organizations that supported them plus the muslim clerics who helped the nazis recruit are representative of the persuasion of that region's muslim population as a whole. That persuasion was nazi.