a fairly significant sign they are an ally.

And the US funding and training the other groups was "a fairly significant sign that they were allies," but you excluded them based on them not technically/formally being allies. If you wanna use that standard, then "fairly significant signs" are irrelevant, the question is whether they have signed a formal military alliance, as in, NATO. As Ukraine is not in NATO, they aren't allied. You don't have to read into the signs, it's an objective fact.

"Security guarantees" aren't alliances. Or if they are, then we're using the term informally, and it's therefore valid to talk about it in the context of funding and training people.

Live by the technicality, die by the technicality. You don't get to have it both ways.