Well, this thread has been well and truly hijacked, hm?
In some ways I understand what mercury says - the idea of folks that only want sex masquerading (and selling themselves) as poly and expecting everyone to go along with it is pretty annoying. Or those that are quite happy to lie and cheat and otherwise be deceptive using the term to get people to enter a relationship with them.
All that gets very tiresome, especially when they start to get defensive and aggressive.
I disagree that "true" poly people never want casual sex, though. Is your relationship with that person a poly relationship when it's based purely on sex that isn't "poly". But that doesn't put any valuation on the relationship - not saying it's better or worse in some way than a poly relationship.