Not 'leftists' at all. The Kurds are mostly Secular (separation of state & religion) in their ideology. In that part of the world, that's way to go vis-à-vis Islamism, particularly right-wing Islamism, as Daesh (ISIS) Sunni/Salafist in this case is.
P.S. - The situation is Very different in that region, and we shouldn’t and can’t judge/assess by political parties in the U.S., or Practically by meaning/definition as it is or would be understood in the U.S.
Daesh? Right Wing?
I don’t see that.
And yes, that part of the world is pressed to fit our definitions concerning government and religion.
When I used the term Leftist it may have been a poor choice of words.
I have read they are communalists. If there is such a word.
ie they are not capitalist in nature.
In that part of the world who knows what really makes sense.
The PKK (Kurdish Workers Party) which has been the primary Kurdish group fighting against Turkey since the 70s is a Marxist terrorist organization.