Though only a remote observer, I think a significant fact that distinguishes the PYD in Syria from the folks in Northern Kurdistan is they don’t appear to adhere to Marxist orthodoxy. In four years of observation I did not detect Marxism as part of SDF ideology. Mildly strict military and social discipline but no overreaching socio economic philosophy other than a form of collectivism that appears to me to have grown out of military necessity based more on cultural norms as opposed to political ideology.