Deep Space 9 was part of the 1990's, and during that time people was thinking of the dark side of science and meeting strange new people. The only way to get dark, was to have a war. Deep Space 9 was not about having cookies and milk parties.
It was working with a space station that was not really federation. It was a part of space that was not really controled by the federation. It was about the political conflict dealing with political interests.