My observation of such has been a Dominant who has many subs (either gender) - so all cool for the Man/Woman who gets more than their fair share of many but where's the fair for the one's who get used but once in awhile here and there? How can that possibly be construed as 'love'? How can you think you're compassionate by holding that person back from having a whole, fully satisfying relationship? They may think that what you are doing to them is what they want, but I imagine they will soon realize they are only being taken advantage of and want something that is for them only.
(Disclaimer: this is all my opinion and it assumes for the purposes of this thread that to be a true Poly, you live in a Poly family and lifestyle, not just someone with many bed partners. Somone who is married and has an on-line sub is not, imo a Poly in anyway.)
Again, to me it just screams Greed/Arrogance/Ignorance for anyone but themselves. It isn't love by any definition to me and quite the opposite, I see it as taking advantage of a submissive's nature to please - just because you fuck someone, doesn't mean you are loving them. Just because they agree to it (thinking all the while, he'll pick me in the end) doesn't mean they like it either.
Yes, I love many people in many different ways, but when in love (it has happened once to me in the past), that's a whole other kind of love.