in the end the whole mess in Iraq and Syria was a direct result of the US invasion and occupation of Iraq. thats what ended up causing isis to be born. Sadam knew how to keep radical islamists in their place. where as the US promoted and used the ethnic differences to help divide and conqour the Iraqis.
as for the Kurds in Syria, they are some 5 to 6% of the Syrian population, they are one of over 20 minorities living in Syria. the US would have had to stay for ever to allow 6% of Syrians to occupy 25% of all Syrian oil and gas resources. it's not a natural state of affairs to have the Kurds dominating all the traditional Arab lands they control now. making the Kurds accept reality and reconcile with the Syrian government is the best and fairest way forward.
you shouldn't compare apples to mellons, the situation in Iraq was very different when Obama left, the Iraqi government was imposed by US military might, it only survived under fortified green zone defended by US mercs.
in Syria the government is strong and has the support of the majority of the population, the SSA has had 8 years of hard core training to keep any new resurgence of isis down and they will keep the Turks out of Syria if the Kurds let them, not the same situation at all. back then in Iraq, the government and army of which,weres totally weak, with the whole army full of paid no show positions, with only half the vehicles working that were being paid to maintain, petrol and weapons sold off etc etc, even top jobs were dependant on bribery and nepotism and or political connections, rather then bravery and skill.
the SSA is a totally different beast from the Iraqi army of back before isis. the SSA have been tested again and again and those still alive and fighting are the survivors of countless battles against insurgents of every stripe all over Syria, they are immensely proud and motivated, moral is high. this is no way comparable to Iraq back when Obama first pulled out.
the territory that the Kurds occupy is land that they protected from ISIS after the Iraqi army threw their weapons down & ran when ISIS attacked. they were the only force in Iraq other than US backed ones that fought back. you don't just hand over what you fought to protect, esp not to someone with no qualms about killing their own citizens. this IS a "natural state of affairs" in that part of the world. you fought for it, you get to fucking keep it. "reconcile with the Syrian government", LOL! the SSA only exists because they are Russian backed and armed. ISIS would slaughter them like sheep on a level playing field...