The prime directive is probably the worst idea conjured up by the creator of star trek. Such a directive is the ultimate excuse for someone to be heartless. In one TNG episode, Picard went as far as allowing an entire race of intelligent beings to die and even went as far as preventing a sociologist from trying to save a remnant of that culture.
You guys seem to debate things based solely on the white and black view. We either not interfere with their culture at all or we go in and wipe them off the face of the earth. To your views, there's no in-between or happy medium.