Fine with me. It's an offensive term and GitHub has every right to police their service and ban content like this. Am I supposed to be concerned by this, and if so, why?
It's surprising how little intellectual honesty there is in modern society. It's even more surprising here that some people (perhaps you) are willing to abandon any rational thinking in favor of their feelings. You seemingly can't comprehend (or are willing to ignore) the logical conclusion to where we're headed.
It's ridiculous for GitHub to police the content on their site in this way. Where does it stop? Will they block commits with "trigger" words?