Why are military men so strict and abusive?

and it's true some of them are abusive towards their wives and children. For example Christina Aguilera's father was a Sergeant in the U.S. Army. He was very controlling, physically and emotionally abusive. Another example is Lisa left eye lopes, her father was a U.S. Army serviceman and he was abusive too. At night he would sleep with a knife cluched to his chest; Lisa and her other siblings couldn't even sleep at night. That's how scared lisa and her siblinngs were of their father. And of we all know Michael Jackson's father was absive. The thought of abuse in a relationship or even your own home turns my stomach and it makes me sick. I hate men who abuse their families and I'm pretty sure anyone else would. I just want to know why they do it.