I agree that the disagreement about whether a helium atom should be considered a molecule is related to what mental framework one slots the question into. I don't think this in any way stops it being a disagreement about definitions of words. (In particular, for the avoidance of doubt, I am not taking "X is a disagreement about definitions" to imply "X is trivial" or anything of the kind.)

The physicist and chemist in Kuhn's story could -- I don't know whether they would if actually asked -- both have said something like this: "It turns out that there are a few different notions close enough together that we use the word "molecule" for all of them, and they don't all agree about what to call a helium atom". Again, this is far from what happens in most political disagreements.

For the avoidance of doubt again, I am not denying that some political disagreements are like this. For instance, there are cases where two sides would both claim to be maximizing equality, but one side means "treat everyone exactly the same" and another means "treat everyone the same but compensate for inequalities X, Y, and Z elsewhere". I suggest that this is actually best considered a disagreement about values rather than about definitions, though. (Each group prefers to define "equality" in a particular way because they think what-they-call-equality is more important than what-the-other-guys-call-equality.)