And... this is why I personally don't believe that people are 100% either! Both of those extremes sound, well extreme! (and a bit unbelievable).
I think it is similar to sexuality - there is a continuum, and the position on the continuum can change for people over the course of their life, or even over a few days. So Legion - yes, I agree with that concept. I have seen it before, maybe on this forum.
Part of the reason I have a hard time grasping the "divide" between things like this is because of these constant changes... I know there are some differences, but it might lie in how we EXPRESS our desires, and not the desires themselves. I think a big part of mainstreaming poly ( or at least minimizing oppression) is to recognize how we are actually more similar than different - that everyone is on the same continuum (planet earth) just in a different spot (town).
I.e. we are all human and our basic needs are the same - we need companionship, a sense of security, freedom, etc.