Turkey makes their own masks now. They share with the US because even though the US chose to support the YPG (an offshoot of the mutual enemy PKK, designated a terrorist organization by both Democrat and Republican administrations), Turkey and the US are still allies.
Hopefully US policy will mature so we can repair the damage done by the support to that group. The reported reason for that partnership between US and YPG was to fight ISIS. But the problem is that YPG only allied with US to fight ISIS to take territory belonging to Syria, not because we’re old allies. We aren’t. We were enemies with PKK, but the Pentagon rebranded fighters to sell the concept to the American public who is not paying attention to such things. It’s a mess. There are no real US allies out of that conflict.
There’s a very fundamental misunderstanding among many Americans, regarding Turkey. People question why we’re friends.
We’re friends because we have common goals and common interests and common values, believe it or not. Our continued friendship, business relationship, and military alliance is valuable and mutually beneficial.
An alliance with communist rebels is not beneficial, especially when it damages our relationship with Turkey, an actual nation and long-standing member of NATO who hosts our military personnel on bases on their soil (even when many EU countries refuse to do so, Turkey stands with us and supports us. We’re the ones who have not shown them support, withholding missile systems while allowing them to partner with us on the F35. It sends mixed signals and makes them turn elsewhere for equipment they need for their defense. Why do they need extra defense? Because we’re supporting their enemy in the neighboring country!)
Source: Quora