The subjective human ethics overlapping with the objective imperatives are actual imperatives; the rest are just preferences.

This redefinition of the word "imperative" goes counter to the existing meaning of the word (which would include all 'preferences'), so it's confusing. I suggest you come up with a new term or word-combination.

I was using the the meaning of imperative as something you 'ought' to do, as in moral imperative. This does not include preferences unless you feel like you have a moral obligation to do what you prefer to do.