I am aware that I do this, which is why I refrain from talking. If you simply insult the human beings inferior to you, you create divisions in which fellow sub-humans aggregate and work together to convince themselves that they deserve the same privileges afforded to the normal and functional. Pretty soon, you will have spit-talking rights activists demanding more prominent and vocal positions at work, not to greater access to water. If you really want to shut them down, you have to be subtle. Smile warmly at them as you casually (but clearly) wipe the salival assault off of yourself. If they apologize, tell them that it's ok but with a tinge of sadness, making them aware of the unjust burden they place on society. With the exception of a few sociopaths, they will become self-conscious and will realize their place in society (that being a distant and quiet one). Trust me, I know this from experience.