That’s not what the post is about. He’s saying that if you’re designing a new language, you should meet these criteria because they are deficiencies in existing

That’s not what the post is about. He’s saying that if you’re designing a new language, you should meet these criteria because they are deficiencies in existing languages. We live with the flaws of old tools because they have other, more important value to us—a new language has no value without adoption, so it had better improve on its predecessors in order to convince people to adopt it.