Yes, the views on child-rearing are particularly unfortunate especially as we now understand that a child would benefit more from a non-abusive environment than from having both parents around.
I think the distinction you make in living polyamorously is crucial. I don't think everyone is the same, but I do think that the capacities for love of a polyamorous person are not so different from that of one who is monogamous. I think most people can, and often do, love multiple people. The real choice is how you actually want to live, and that's what the different styles of relationships represent (ways of living).
I should have clarified. I did not mean inherent in the perception of monogamy. I meant inherent in the reality of monogamy. I think it's impossible to have a monogamous relationship where there will not be feelings or desires for others thus it's inherent in the reality of monogamy regardless of the common perception (which I agree with you on).
The study of love and sexuality as humans experience it is fascinating of course, but it's a question best left for science. I think of crucial concern to the larger public is what choices we have the ability to make and what the results of those choices are. It's an arena with precious little literature or study. Books on polyamory with any degree of intellectual rigor are staggeringly rare, and books on the entire spectrum of relationship choices/lifestyles as a whole and the realities of them without an agenda are nearly, if not entirely, non-existent.
I have no proof, but based on my reading I would estimate that the vast majority of relationship counselors of any kind still advocate that there's only one correct type of relationship. Of course it's a different type or version for all of them. Being that these are the people most often looked to for guidance, we've got a long way to go.