Shaved head(bōzu) of high school baseball

Why does a high school baseball team member make a shaved head(bōzu) hairstyle? There used to be some crew cut at some high school before, but why shaved head(bōzu)?

You may often hear people who give up to entering baseball team because they do not like be a shaved head(bōzu), it is a bit disappointing to give up baseball for that reason. Also, some of them may have the potential to become super class player.

When I am watching high school baseball, everyone looks the same. I cannot see the personality at all. It may because everyone has same hair style, shaved head(bōzu). It is a bit disappointing.

A little thing come to my mind, high school baseball members are arranging eyebrows by shaving or cutting them. This may be because the members are appealing their own personality.