I will allow some reaction......baseball is a passionate game and its natural for a player to react either positively or negatively to a call... But using profanity, making a personal attack on the umpire or making physical contact with an Umpire will get you tossed.....
Now over the years I have a very low ejection rate... that being said, Players get little leeway here.....it is not your job to argue with an umpire, that is your head coaches job......