The 97% white men stat is easy to explain: I imagine it difficult to really prove yourself against implicit bias in the humanities.
Or an even better explanation which also explains STEM disparities: men tend to like subjects that deal with things, women tend to like subjects that deal with people (things vs. people is well studied gendered phenomenon). Notice how she seems to spend a lot of time talking about how boring, unimportant and disconnected her topic is from the real world...