certainly less calendaring and meeting invites, I'm sure. I did meet a couple of people who identified as non-monogamous well after I had met my very monogamous partner (whom I love deeply and am happily monogamous for) who seemed very cool and were equally put off by the polyamorists they had interacted with. but they were truly diamonds in the rough, at least in my major metropolitan city, and not a single one of them was hetero or close to being a WASP so you're probably right about the cultural tidbit