I think that mothering has made the stance on numerous occasions that their reasoning for not having forums for support for many of these things (particularly formula and circing for religious or medical reasons) is because so many other parenting sites provide support for those issues. In a community of people who primarily breastfeed, it's not the greatest place to get tons of opinions on bottle nipples.
Babycenter and DiaperSwappers have tons and tons of threads where 100s of people give their opinion and experiences on those types of things. I have accounts at both of those places specifically for things that Mothering doesnt provide. They have a HUGE infant loss forum, a bunch of opinions on "stuff" that most people at MDC dont use/want/need, and forums for things that are a little more mainstream. If you ask about an organic formula here, you are going to get 10 million tips for breastfeeding, reasons that your doctor is wrong about telling you to supplement, and opinions on what you should be doing instead of feeding formula. If you ask on a different forum, you'll get 50 different women telling you what their kids drank and why they chose that formula. Some things are just not the greatest topics for this community. Recently, MDC has added a forum for moms who have had C-sections, which I think was a fantastic addition. I have seen much fewer arguments about C sections since that forum went up.
That being said, I think that MDC has not been able to cater to almost half of their community in regards to vaccination topics because so many of us DO choose to vax (selectively, delayed, or thoughtfully on schedule) and tire easily of defending our decisions from the 10 die-hard anti-vax posters who will argue with anything that gets posted in the forum. .But, as I've said before, I think there should be a vax board that talks about everything vax and then a board just for people who don't vax.