What you are saying is true and crucial to understand. The same observation applies to a lot of named concepts in academia (in voting/game theory and economics

What you are saying is true and crucial to understand. The same observation applies to a lot of named concepts in academia (in voting/game theory and economics especially). However, I also think that results in these fields can be useful in political discussions, as long as they're used as thinking devices rather than arguments in and of themselves. The map is not the territory, but "price of anarchy" is a suggestive name. The name suggests, purposefully or not, that this set of mathematical results about an abstract game theoretic model might be useful to hold in mind while thinking about political systems. And I don't think that's necessarily a bad suggestion.