It comes back to that implicit expectation. Something I've been bringing up a lot in this thread as I read the comments throughout it is that whether we consider somebody rude or not seems to depend a lot on a) who they are, and b) whether we agree with them. We are more charitable to people who are more like us and whose ideas we find more correct. We're all human, so that's part of life. However, as an organization, Github can and should do better than that, and I think here that it did not. The sexism here, if it exists, is implicit in the way problems with this person were handled and in the expectations (mostly unwritten, at least at first) about how she'd behave.