I think diversity is not exactly an end in and on itself, but a way to reduce general inequality. Increasing the number of woman in fishing, or logging, or coal mining is not going to have as much effect on the general economic/social power of women as doing the same on bigger, richer industries such as programming. As resources are limited, you want to be as efficient as possible and that will probably shift the focus away from industries that are not that influential. Of course the fact that they're not as attractive is also relevant, but it seems that being non-attractive and being less important are correlated features in an industry sector.