Do you really feel "we are a minority that would be reviled more than almost any other?" Poly is becoming more and more known, written about, reported on, and publicized, and I don't think it's true that polyfolk are more reviled than others.
And as far as being a chosen community, that is pretty much the case with any group of like-minded individuals or people with the same or similar interests. Of course people will seek others with whom they can share passions, interests, connection, camaraderie, etc. That's not very unusual.
I answered 0 to 20%.