I would bet the batter was mouthing off to the pitcher.
My son played in the Coastal Carolina League one summer. A batter hit a HR off one of his teammates, flipped his bat and trash talked the pitcher as he was rounding the bases. The next time he came up, my son was pitching and he buried a fastball right between the kid's shoulder blades. The batter shouted at the ump "He hit me on purpose, aren't you going to throw him out of the game?" The ump replied, "The next time you hit a home run, don't be a jerk about it. Shut up and take your base." That's the way the game is properly policed.