I don't know if they all actually left but that's what the traitor in chief wanted.
Amid growing chaos in Syria, Donald Trump has ordered all US troops to withdraw from the country’s north to avoid a bloody conflict between Turkey and formerly US-backed Kurdish fighters that “gets worse by the hour”, the defense secretary, Mark Esper, said on Sunday.
https://www.theguardian.com/world/2019/oct/13/trump-us-troops-northern-syria-turkish-assault-kurds