If they really want to catch these people, you wont be seeing only a few examples over half a decade. As mentioned in the article, even Hu Xijin (the former editor-in-chief and party secretary of the conservative popular media Global Times) has a youtube channel. Most top universities like tsinghua, SJTU and tech companies like alibaba have official github accounts.

There is no way to implement complete censorship without killing your own tech industry.