I think, poly or not, we all bring our prejudices into every aspect of our lives. Here in Philly, the poly group is mostly White but its not because they haven't reached out to other races, it because other races haven't wanted to be a part of their particular circle. I don't know why, really. Fear? Distrust? Hate? Probably all those things. My wife and I, being an interracial couple, have pretty much just been shit-out-of-luck LOL when it comes to poly and/or swinging. Blacks have issues with her being White, or have all these really oppressive stereotypes about her as a White Woman, or vice versa. So, yeah...Philly is not the place for poly.
I still think MOST people, of all races, just cheat and have affairs. Poly demands that you show up as a whole person, be honest, be respectful, and deal with your shit on a constant basis. I don't know that a lot of people are ready or willing to do the work. Hell, truth be told, we're not really ready for it so we are doing the monogamishlike thing again LOL.
You talk about forgiveness? I feel like that can only come when people are ready to just say "Okay, some bad shit happened back in the day but we can make new choices and move on from here." I don't know that many people, again, are ready and willing to do even that. Our hate and fear keeps us safe, or at least makes us feel safe.
Good luck in Seattle. My wife is from Redmond, actually...well, sort of...