Bush League to me is doing anything ungentlemanlike to try and distract the pitcher or batter from playing his best. There is a team in our league that is obnoxious in this way. They will make bird calls at the pitcher and shake the fence just as a ball comes into the strike zone. Their chanting from the dugout is never positive, always against their opponents and excessive. At our last game against them, a parent on their side came over to sit on our side. They were that embarrassed.
They are getting a reputation for being a "classless" program. Unfortunately, they've had some pretty good ballplayers get passed by to play at the college level and you can't help but think that somebody was watching.
Not surprisingly, since their chanting has gotten worse, so has their team.