Just playing Devil's Advocate (I actually agree with you), couldn't it be argued that the catcher is distracting the batter by yelling? Bunting takes skill and that could startle the batter and cause her to miss the ball altogether.
Maybe it could be argued, but I would be very surprised if it got the arguer anywhere. The catcher isn't trying to confuse the batter, or trying to distract them into doing something different. It's common defensive communication.