If they are communist as a whole, and I'm not convinced the majority are, it is due to lack of choice. USA & EU has long ignored them in favor of their enemy (Turkey). If one is desperate enough, the logical choice then becomes China or Russia to cozy up to. That said, the majority of Kurds are definitely Sunni or Shia islamaholics, and as such are unreliable allies. With all its problems, Turkey has so far managed to avoid sharia. I much doubt the Kurds would do the same if given their own government.