You haven't responded to the idea that the US can't be trusted and by your arguments I assess you agree the US can't be trusted.
That ship sailed for me in 2009 when Obama abandoned a number of Iraqis and Afghanis who had aided us previously, and was cemented in place when Obama failed to honor the agreement with Ukraine.
So cry me a river when Democrats start whining about how "Trump just proved the US can't be trusted." At this point, I'd rather see the US avoid perpetuating agreements we have no intention of honoring in the long term.
I think the only difference is gradual distancing and abandonment versus dropping somebody cold. We usually ghost our former allies of convenience rather than crushing them more directly. That's not much of a difference, and I suspect the Kurds always knew they were cannon fodder.
1974-75 : Kurds get lured into war with Hussein's Iraq, the Shah's Iran and the US laugh it up. Hundreds of Kurds were executed. Kissinger: ‘Covert action should not be confused with missionary work’.
1988: Kurds get gassed. America who? Never heard of em.
1990-91: Kurds rise up against Hussein again. We give them some air cover, but sent arms that led to some sweet Kurd-on-Kurd attacks.
So we got Ford, Reagan, and Bush at a minimum screwing them over. It wouldn't be hard to add Obama in there as well, most likely. And now Trump.
It's about the only Presidential tradition Trump seems to want to keep. The Screwing of the Kurds is about as Presidential as it gets. It's about as funny as Lucy pulling the football away from Charlie Brown, only in this version Charlie cracks his skull open.