Very new here, but I see what polypenguin is saying.
People are inherently good or bad. However, even good people can make bad decisions when they feel they're against the wall. Poly is an alternative lifestyle. Some people feel they cannot be open about their lifestyle in everyday life, and therefore suppress their feelings until it all boils over & they do something foolish & selfish.
Not that it's right. If the world was good & right, there would be no closets to hide in because there would be no need.