Remembering this history is important for a few reasons. First, much as the conservative right tries to label everything liberals do as radicalism, progressives should recognize that part of the proud history of the left (broadly speaking) has been radical forces pushing the big visions and often pointing to injustices before anyone else. Second, the origins of International Women's Day remind us that to concentrate too much on specific issue silos (labor, feminism, GLBTQ, etc.) makes us miss the interconnections among them.
This is not to say that one must devote oneself to all issues equally, but to at least acknowledge the relationships is vital. Certainly on the conservative right such relations are recognized; one can see this in the fact that many of the same GOP governors who have flexed their legislative muscles in attacks on labor rights have also targeted women's health. At the same time, it is important not to become carried away by the overlaps, as with those who attempt to create a model where one core issue sits as a sun, with other issues as mere orbiting planets, miss the point. For example, the marginalization of women has strong economic components - that does not mean it is a mere function of our economic system (newsflash: the oppression of women is a much older feature of society than capitalism). And it is only natural that personal interests and experiences will direct people to specific causes. We should instead always endeavor, whether it is in how we frame a public address or how a coalition is constructed, to at least be aware of how interdependent all of these causes are.