Funny how people are really responding to the kids or no kids issue, though I didn't think that was RP's focus in her original post. Must be a sensitive issue for many. Now in re-reading it, maybe that is a big part of the question, but it seems that the divide between "poly family" (however one defines family) and a much looser practice of poly, was her main concern or at least what prompted the question.
As a kid, I used to fantasize about being part of a big family. But as I got older, I have come to enjoy my solitude and independence, although there are times I am quite lonesome. A poly tribe, or big poly family, is nothing I would ever want, whether there were kids in the equation or not. Maybe if I were still in my 20s or 30s, I'd be into it - but now in my 50s? Nuh-uh. It probably does have largely to do with my lifelong choice to be childfree, but not the only reason. I relish my privacy, and have had enough roommates from hell to find communal living rather off-putting. In embracing poly, I reignited an old dream of mine to be a truly independent woman openly living on her own with a number of lovers.
Now, getting to the question of divisions in the poly community...
I believe any divisions we do see will mostly be predicated upon our own experiences and viewpoints. I guess the "poly family" question is a non-issue for me, since I am satisfied with my choice and don't find myself in situations where it is challenged. And in NYC I don't seem to meet many people trying to build a poly tribe (real estate being a huge factor, probably!). So, I don't notice a divide so much from that perspective, but more so from the view of solo vs. married. For example, I frequently reach a saturation point at which I cannot hear one more story about opening up a marriage, or the struggles of a couple dealing with their "thirds" or in-laws or whatever. I want to hear more from solo poly people who choose not to have any primaries. For me, it's a divide I feel a lot, because I am alone and set apart from most of the people I've met at the few poly gatherings I've attended, and here, and other poly forums I have visited. I find it exasperating when someone says to me, "But you're not poly, you're just dating." It has happened.
That's one divide I see, but if I look at how I feel when I'm in a poly group, I see more -- these are all based on my choices that seem different from the majority of those who go to hang out at poly gatherings (being solo, a straight woman, not into kink, etc.). For me, I have never felt like I fit in anywhere in my entire life, so I think I'm used to it, sad though that may seem. Now, I have not experienced any outright rejection from the poly community, so I think the divisions I see are totally subjective. As I stated earlier, I don't see the need to label myself or be part of some organized poly machine, so it doesn't affect me much, other than bring up some occasional feelings of frustration.
Geez, I fucking hope that made some sense, I got distracted halfway through writing it.