.
The same reason why, when they launch a surprise attack we call it a dastardly sneak attack; but when we do it we call it a courageous raid.
You might also consider the adjectives used in DTTs question 3 places before this one.
Democrats can get cheesy. Guilty. But I would rather have a plate of cheese than a plate of what comes out of a bull's rear end. That plate is what is offered from the right wing sphincter muscles of the entitled GOP.