In my opinion, “cunt”, “pussy”, “dickhead”, and other anatomical slurs, aren’t actually descriptive of anything. Clearly, the person is not a giant talking yoni, so the expression has only the power that the speaker and listener choose to attribute to it.
“Lazy”, “stupid”, “worthless”, etc. mean something. They are pointing out a specific perceived attribute of a person and attacking them with it.
That is much more offensive, in my opinion.