I think it depends upon the issue CCl. Fortunately there are lots of different areas of MN, so if you wanted to talk about gender in relationships, you could do so on the relationship boards. If you wanted to talk about gender in mental health, you could do so on the mental health board. But if you wanted to talk about any issue in terms of a feminist perspective, you could do so on the feminist board. So you always have both options - gender or feminism.
I don't think the proportion of people who make up a disadvantaged group makes a difference to whether or not that group's issues should be discussed in isolation.
People with a special need in the UK are a minority in numbers and in amount of power.
People who are black in South Africa are a majority in numbers and a minority in amount of power.
Women in the UK and worldwide are neither a majority or a minority in numbers but are a minority in amount of power.
I really don't see how the number of people involved one way or another makes a difference to whether or not the needs of the specific group should be looked at as individual issue, at least some of the time.
For example, having reproductive health centres for women and having planning groups that deal solely with those centres doesn't stop another group discussing those centres as part of wider planning, or prevent another specialist group setting up facilities for gay men. It doesn't mean the group talking about women's health don't care about gay men -it just means it isn't their focus right now, in that group.