The liberal, politically correct part of me wants to say that polyamoury is fine if all parties are consenting adults, and if it works for them then who am I to judge and all that.
My instinctive feeling though, based largely on the people I have met who define themselves as polyamourous, is that it's a bullcrap "get out clause" for being a ****. It seems a lot of people want to be able to ***** around and defend themselves by saying "Hey, I'm polyamourous and it's a valid lifestyle choice, you can't judge me!"
I don't know that I trust "instinctive feelings" on this kind of issue though... Just because the idea repulses me it doesn't make it wrong.