The Middle East is a complicated place.
The Kurds have been America's allies over the past twenty years. The Kurds were fighting Saddam prior to Desert Storm. The Kurds were fighting ISIS prior to America entering that war. So you already gave the answer how the Kurds supported america.
It can be argued that America did more for the Kurds than the Kurds did for America.
The Kurds have also been at war with Turkey through terrorist acts. Does Turkey have the right to defend it's self?
the PKK (party) is so classified, not 35 million Kurds living in different countries.
Thousands of villages have been destroyed by Saddam, hundreds of Nato member Erdogan, and the West is silent about it.
Kurds want their own state.
Erdogan is occupying parts of Syria contrary to international law.
Putin the Krim , an embargo against Russia, not against Turkey...............
Everyone pulls their tails in in front of the fanatical muslim Erdogan.
How much longer ?
Muslims fight against muslims
Is supposed to be a peaceful religion.
Then please explain to me why millions of muslims are on the run from muslims who want to kill them.
Does America have a treaty with the Kurds? They certainly have a treaty with Turkey. It is called NATO. Turkey has been an ally with America for much longer than they have the Kurds. All throughout the cold war. Technically America is responsible for defending Turkey against aggression.
Amerika needed Turkey as a strateic partner in the Cold War.
Europe does not need it (up to the refugee crisis,that's why Europe keeps its mouth shut).
At this point, none of us know exactly what is going on.(I have not seen any news today) Is Turkey even going to attack the Kurds, or do they have other objectives. We also don't know what has been communicated between Erdogan and Trump. Did Erdogan tell Trump he was going into northern Syria regardless of what Trump did. Does America want to risk a war with Turkey by leaving 100 or so soldiers in harms way.
Who did the much of the heavy fighting against ISIS? What was the roll of the GCC? The GCC hardly acknowledges their own existence, much less anything they do. They don't look for any recognition. Does the GCC have an alliance with the Kurds?
Trump told Erdogan that he would destroy the Turkish economy if they did anything out of line. Stopping access to the SWIFT system would certainly do that. Perhaps Trump is deciding to fight economically in lieu of using military action.
Erdogan is an easy person to dislike and distrust. The Kurds, as an underdog are easy to root for.
This is probably much more complicated than any of us realize. Time will tell.