This has got to be the dumbest debate I think Ive ever witnessed. If you dont understand why things are done just leave it at that. your morals arent going to change the game.
as Indy already said, Ooops that slipped will always be in a pitchers vocabulary. The pitcher is the one with the ball in his hand. Even though technically the pitcher is on defense, He is the one with the ball and the hitters should respect that and in a way fear it. The ball could "slip" at any moment. So why be an idiot and taunt him?
But not all brushback pitches are meant to hit the batter. Sometimes its to do just that. Brush them back off the plate. Take Votto for instance. The next plate appearance when votto stands in, if Darvish is still pitching, chances are votto is going to be pretty confident and comfortable in there after just going yard. So how do you break someones confidence? Remind him you are the one with the ball and "sometimes you arent that accurate" Not hitting the batter, but throwing inside to ALSO (knowing you arent going to hit him) set up your next few pitches. If you brush him off the plate you are almost setting up a breaking ball on the outside corner or a fast ball low and inside.
And like someone else already stated there is a written rule and a penalty for someone who hits a batter. But you cant just start throwing people in jail (isnt that what you get for assault) for every batter hit. Because the line already stated before and probably a million times in this debate already. All the pitcher has to say is oooopps my bad it slipped. And if its the second hit batter of the game he could get ejected, depending on the umpire and fined.