What would you say is the difference between a fringe and a minority?
I think the distinction is that we usually refer to minorities in the context of a set of defined characteristics that individuals inherently have or do not have and where it isn't a choice. So in the UK black people represent a minority as you are either black or you are not black, and if you are not black you cannot become black and vice versa. So the total pool of potential black people is the same as the actual pool of black people - in other words black people are a minority in this example.
Religion and other belief positions (whether religious, philosophical or political) are not like that. The potential pool of christians is 100% of the population - anyone can choose to be a christian - likewise humanist - likewise socialist. So it is perhaps less appropriate to call people who hold a view that could be adopted by 100% of the population to be a minority - rather we should describe the view or opinion as a minority or fringe one.
Point being that we could all be christian, or humanist or socialist, but we cannot all be black.