What needs to be also said is that there was an unwritten agreement between Syria and the Kurds -- Kurds do not attack Christian enclaves like Hasakeh and assist them, Assad does not attack Kurdish enclaves like in Aleppo and assists them.
And while it is nice to see US-supported Kurds driving out US-supported ISIS, they are taking over non-Kurdish territories (from Sunni Arabs and Turkomans)... this will cause more wars and more refugees.