"The whole thing functions as a big rubber stamp on What I Already Thought"

Speaking as a (probably biased) consequentialist, I generally got the impression that this was pretty much the whole point of Deontology.

However, the example of Kant being against lying seems to go against my impression. Kantian deontology is based on reasoning things about your rules, so it seems to be consistent in that case.

Still, it seems to me that more mainstream Deontology allows you to simply make up new categories of acts (ex. lying is wrong, but lying to murderers is OK) in order to justify your intuitive response to a thought experiment. How common is it for Deontologists to go "yeah, this action has utterly horrific consequences, but that's fine because it's the correct action", the way it is for Consequentialists to do the reverse? (again noting that I've now heard about the example of Kant, I might be confusing Deontology with "inuitive morality" or "the noncentral fallacy".)