Kant's categorical imperative is a circlular argument from religion - bad things are bad because they're bad, good things are good because they're good. He advocated for telling a murderer where their intended victim is, because lying is categorically wrong [1]. Deontology can only be justified by religion; utilitarianism (ethics come from the outcome) is the better option.

Also Kant positioning himself as a moral philosopher is pretty ironic because he was insanely racist.

1: https://en.m.wikipedia.org/wiki/Categorical_imperative

> One of the first major challenges to Kant's reasoning came from the French philosopher Benjamin Constant, who asserted that since truth telling must be universal, according to Kant's theories, one must (if asked) tell a known murderer the location of his prey. This challenge occurred while Kant was still alive, and his response was the essay On a Supposed Right to Tell Lies from Benevolent Motives (sometimes translated On a Supposed Right to Lie because of Philanthropic Concerns). In this reply, Kant agreed with Constant's inference, that from Kant's own premises one must infer a moral duty not to lie to a murderer.