ss. Let's differentiate between two uses of the word "can". I'm sure you'll get it because even shit for brains can get it.
Can, in the sense you are using it, indicates the (perhaps logical) possibility of the action. You can, for instance continue acting like a piece of shit. You can, for instance, not try to understand what makes you a defective moral agent.
In language we also often use the word can in a more restrictive sense. I could say you can't rebut in anyway you like. If you asked me why, I wouldn't say it was logically impossible, but because you can't do it without being an asshole, or rather, without failing as a (supposed) moral agent. Because it is wrong.
In this way we can, incidentally, see how this more restrictive usage, can have an explanatory qualifier added to it, and thereby retain the same meaning as in the first case. It is not possible - you can't, rebut anyway you like, without being an asshole.