While I don't agree with the tone of the author, I do have to admit, there seems to be something foundationally wrong with front-end development. Yes, it's more complicated than server development in that it is a real-time, multi-point input, multi-output (rendered elements on screen) environment with synchronisation and concurrency needs.
But I used to write front end applications with MFC (Microsoft Foundation Classes, which is C++) using Visual Studio circa 2005, and it was never as complex as an SPA today. There is something wrong somewhere, and I don't think it's JavaScript or the DOM. The flaw seems to be paradigmatic.