this is in the same category as "the law in its majestic equality forbids both beggars and rich men to sleep under bridges".
DHH advocates "no politics at work" because as a powerful guy that's organized politics potentially directed at him. He advocates blogging because he knows perfectly well that he has a large audience and his employees or critics don't. That's why the rich tech bro class loves getting politics out of the workplace and getting it onto the platforms they own.