I'm not trying to defend the example in detail—I agree that they don't have an obvious, rigorous categorical connection. I broadly think that with so little pol

I'm not trying to defend the example in detail—I agree that they don't have an obvious, rigorous categorical connection. I broadly think that with so little polymorphism you're not going to get a terrific categorical reading. I agree with the op that they still "feel" adjoint and may have a better reading there with a little generalization. But yeah, it's not the greatest example. I don't mean to defend it as something rigorous.