Your comment is dead on. OAuth2 provides a way for people to log into your service without really telling you who they are. Instead, you outsource the task of asking them who they are to another company. But if you don't care who your customers are, why are you asking them to log in?

The whole concept makes no sense. And then when you consider that OAuth2 isn't even a protocol, but a "framework for a protocol," whatever that means. But sites use it, and will continue to use it, because it makes signup easier for new users.

Here is what the author is missing from is "programming is hard" angle. Yes, programming is hard, but that in itself is not a bad thing, and it's even a good thing if the program itself is a good idea. But OAuth2 is not a good idea. It's not even a bad idea -- it's a framework for a bad idea.