I think it is problematic that many people in non-hierarchical relationships use primary and secondary labels. This is particularly when thinking about polyamory in relation to mainstream monogamous culture. I am sure that to many monogamists the terms primary and secondary refer to hierarchy (as they seem to do for many poly people, while not for many others, based on this discussion). Therefore, hearing those terms to be commonly used by many poly people, even in non-hierarchical relationships, gives the picture that poly relationships are most often hierarchical. Of course, even a poly structure where there actually is a more and a less important relationship still challenges the mainstream monogamous culture. But using hierarchical language in polyamorous relationships, even in ones that are equally important, enforces the so common belief that people really can't love equally, i.e. one must love one more than the other or polyamory involves no Real Love at all.