you are projecting your feelings now. anyone who has been in a club must have encountered an abrasive drunk atleast once, its how you react towards them that is telling of what kind of person you are.
They are drunk so they have no control, but you being sober have control over your actions. and if you fail to show empathy and forgive them, then it reflects poorly on you. spit comes right of with a bit of cleaning, but beating a guy up for doing something he didnt have control over is not justifiable.