So the title is just clickbait
(So what is this article talking about? I guess it's talking mainly about "Write programs to handle text streams, because that is a universal interface".)
Go check the man pages of any commercial UNIX to see how many of the commands actually abid by such famous phylosophy that gets passed around, of each command doing a single thing well.
It is a endless list of options, and multiple capabilities for each of them.
No, users were used to it because that's how Google works.
> [...]
> If this reads like gibberish to you, my younger hothead self, full of (neo)vim and vigor, would have hit you with the old “Linux is very user-friendly; it’s just also super picky about its friends.” Yes, younger me was adept at making enemies like a craftsman
No, it reads like you are an entitled fanboi and need to touch gra^W^W talk with a real human beings outside your small citrcle of nerds. Even better - to work a couple of weeks with your own hands and your own back. That helps.