Overall I think the point is who cares what caused an increase in labor supply? It doesn't matter from where Marx's reserve army originates, just that capitalists desire and ensure that it exists to the detriment of the working class.
Again, the composition of the industrial reserve really isn't the point. They're the able to work and unemployed. Whether we have at times integrated previously unused reserves on the basis of race or gender or class is basically irrelevant. The point is the fact of the reserve - that it exists. Look at 2008 on, we've had quite a substantial reserve with quite a diverse composition. But it's there, ensuring that wages won't rise (or rise much) during the boom times.
Perhaps we might have a better discussion if you told me what it is you're actually driving at because I'm not quite sure I see it.
