I think since the premise of the author's article is that everyone should have a place where they can take more deliberate care of their online presence, it's pretty reasonable to infer that it goes without saying that one shouldn't use pejoratives like "retard" except in cases where the word itself is under discussion (like critiquing the use of the word in society, as we're doing now). Even still, I'd consider that a pretty hazardous topic to write about unless I were a linguist or in some field that made it appropriate to discuss it intellectually.

Admittedly, it's not clear whether GitHub would take down such a repository/site, but my hunch is that when it's deliberate and not casually thrown around, people wouldn't have as much footing to complain about a charged word. That being said, I'm not willing to test it, which says your point has merit just by virtue of a chilling effect.

Nevertheless, a sibling comment mentions using S3, which (I think) would be less likely to get taken down (although I've never heard of Amazon outright refusing to take down such content, so maybe the request simply hasn't happened yet).