This creates and easy explanation/scapegoat for a problem rather than trying to actually figure out all variables involved.
It very well could be that when taking into account all the variables, it is systematic sexism/racism or whatever the claim may be. However one should be careful to jump on the ship that claims sexism/racism first without looking at all the other reasons and factors that could be at work. (Biological differences, family vs career importance, instances of sexism/racism, instances of reverse sexism/racism [helping an individual solely based on their race/sex], subjective influence, personal upbringing etc.)