I don’t think that delivering a “douche-slap,” even to a clueless idiot who “deserves” it, benefits anyone.
The target of one’s wit is liable to be resentful and eventually angry, which will most likely only drive him deeper into his misogyny.
More important is how it affects her who does the slapping. She may come to believe that the best and most satisfying response to infuriating behavior is to return even more infuriating behavior. The world is already overflowing with hostility, I don’t think creating more will help.
How much happier and healthier is she, who so masters herself that the inevitable posers of the world no longer have the power to infuriate her in the first place?
Pro tip: Nobody will ever give a fuck what you think if you come at them like a sanctimonious fortune cookie.