Look at it this way. If I told you every time a coin came up heads, how many reports would it take for you to conclude that it was biased? The right answer is "the conclusion may never be reached," because I'm not allowing you to tally up the number of times it came up tails. Likewise, despite the huge number of stories about women being denied appointments despite having made significant contributions, no conclusion can be drawn until there is some indication that the effect is unique to women.

Another important point is that even if the 1930s were awful and sexist, there may have been islands of relatively fair people. So in the interest of remembing them as they deserve, it is best to check each social group individually for evidence of their bad behavior, so that you don't end up remembering the one admissions committee that wasn't sexist as just another bias enforcement team.