It's not a monogamous problem at all. Polyamory involves having multiple loves, right? Multiple romantic relationships? I mean nobody in a healthy monogamous relationship had a limit on how many non romantic relationships they can have. Well for me, and a sizeable amount of the population, regardless of their relationship orientation, need sex for a relationship to fall under the romantic category, to include the possibility of love. I know some people don't, and I know that some people who would feel that way if they had to have monogamous relationships for whatever reason. Ie, as you said polyamory offers the opportunity for you to get your needs met from more than one source. But, they have the ability to feel romantically for someone they do not have sex with. I don't. Many people don't. So a relationship without sex would only ever be a friendship.
Tl;dr - that suggests to me that you can love people you're not fucking, I can't, so they'd only ever be a friend.