So when exactly has that non-mixed-sex workplace existed? It hasn't, the mixed nature was just buried under ungodly amounts of hierarchy full of gender defaults. With harassment just taken as a given. Partially held in check by, well, good guys who I guess have always existed, and the ones from the dark ages must have been very good given the lack of external checks, but those 20 or whatever percent who weren't must have made life quite miserable for those at the wrong side of the default imbalance. Yes, progress has happened but we should still have more of it, not less. And HR plays a role in this progress, even if at times it appears a little annoying or excessive.