What is/are the root issue(s) of this mistaken belief? I typed a few possibilities but they sounded preposterous so I just deleted all that.
Could someone who thinks this is censorship please explain why Github doesn't have the right to control its own privately owned website, and how one single website monitoring the language used there is equivalent to a government "universally" (well, within its borders) coercively prohibiting all such content, such that the person in question is prevented from publishing it anywhere else, even by themselves?