The SDF is the Kurdish-led group fighting ISIS in Syria. They seriously kill ISIS, and have taken almost the whole North of the Country from them. All without accumulating any prisoner population to speak of.
The witches brew of assorted Sunni jihadi “moderate” rebels are the ones who hand over their heavy weapons to their jihadi brothers in al Queda and ISIS.
Maybe we have "old-school" military advisers on the ground working with them instead of your more typical ObaMao appointees vetted by Valarie Jarrett.