These are much needed spaces and I would love to see these circles grow! I know many lesbians are frustrated with bi women posting and commenting in their space while bi women want their own space.
WoC also have separate experiences they want to discuss in their own circle apart from non-WoC. WoC can't build as strong of a community without their own space, or at least not as easily.
And finally mental health is really just such a big category on its own but arguably doesn't fit into the health circle. Many women struggling with mental health (including myself) may have an aversion to having to sort through physical health topics to find support and a community.