It's to protect the other countries from their selfs... We have bases on our allies soil, neutral allies, and most of our some what hostile countries. Why do they do it? Many reason and not many that would sound good in a scenarios... Many people in other countries protest daily about the bases, in Japan there have been reports of some soldier misconduct, and it's one of the reason that the terrorist hate us for having bases on their sacred soil. It's not all bad though, I know many people in Germany that get along with friends of mine that work on base. One of my relatives is stationed in Germany because of her husband works for the military, and she is a teacher that teachs both German and american kids.