I don't think the examples add up. Like, yes, if the system has a way to do auth then you should use it. But if the system's way of doing auth has nasty surprises, rather than cargo-cult the workaround to those nasty surprises, you should fix them! (Especially if the article wants to argue that adding inconsistency is bad - then by the same token removing the inconsistency that someone added before you is good). And if the system has its own custom auth implementation that does the same thing as a standard library, you should probably pull it out completely and replace it with that standard library.