It's tough to say that Ukraine and US are allies right now. US refuses to hold security assurance, as promised, and forbids Ukraine to restore nuclear arsenal, as before the promise. Bullies behave is such way, not allies.
It is irrelevant to my interpretation of the aforementioned parent comment.
The point is that US made Ukraine do something that the US wanted to do but did not do because were it the US, then it would have had repercussions on US, so they made Ukraine do their dirty work.
