Feminist economics, I assume, doesn't axiomatize.

Why would you assume that? If you're willing to reject the principle of bivalence (and thus "logic" as ordinarily understood), you're free to take some "core" of morality as axiomatic and use "fuzzy" reasoning to reach formal conclusions. Admittedly, feminist economics probably doesn't do that, at least not yet. But an AI built to follow feminist or Islamic principles could.

I don't know what you're talking about. The Categorical Imperative is a rule. Its the rule. The only rule. The impact of a given action has exactly zero to do with it's morality according to Kant.

You're clearly thinking about "moral philosophy" as practiced by Western academic philosophers, not "ethics", "morals" and "rules" as most people actually understand these terms. Yes, Kant was trying to define a rule-based morality, and he stated as much. But the Categorical Imperative is not more of a rule than the Utilitarian Imperative is--"choose actions which maximize world Gross National Happiness (or some other index of total well-being)". It is actually closer to "ethics" as a form of dispute resolution between conflicting rights (or "principles of rational agency" as Kant would say), rather than "morality" as understood by most people, i.e. divine command theory/moral absolutism: "I am right and you are wrong and you should do what I say".

Nobody cares about what Kant wrote or thought about his theories, unless they're a scholar who's specifically interested in that. Besides, most LWers know that a lot of Western philosophy is hopelessly garbled and should be reanalyzed from scratch if it is to be practically useful.