Why is that a surprise? "Toxic culture" in relation to Riot and Uber is basically defined as a "sexist bro-fest" and women being allowed to work the same jobs as men is a relatively new thing (historically speaking) and thus is still being fought on many fronts.
Also look at e.g. Japan where women in the workplace are generally treated quite badly. There was a thread on HN yesterday or the day before which reinforced this trend.