Kurds want to survive this, and keep the turf they have captured from ISIS.
We won’t help them.
So, they’re getting help elsewhere.
Why we’re doing anything helpful for Turkey is the question of the day.
Exactly. They aren't doing this for ideological or religious reasons, but practical ones. Kurds got a better deal under Assad than they ever would under ISIS or Al Nusra (who the Turks may not like but probably prefer to Assad), and so would rather have him in power than any of the likely alternatives. The same is true of Syrian Christians and Yazidis.