I disagree. Headless code on a single server can still be very difficult. For instance, nginx, mariadb, etc, which allow the frontend to function well, are difficult to write. You have to deal with multiple threads, search algorithms, handling tcp/udp requests, and optimizing all of that so it isn't dead slow. Whereas writing GUI in JS/React involves less "computer science" complexity and more compatibility complexity-dealing with things like, what is the screen-size, the locale, etc.

On the note of the HN's perceived hatred of JS, I think its because Javascript has tried to do too many things. Despite its quirks I like Javascript in the context of the web browser, but what I dislike it that it exists in applications and on the server side. The Atom editor should not take up 200 MB and take forever to boot. But it does because instead of taking the time (like sublime text) to write a rockstar system code, they instead used electron. The feeling I get sometimes is that JS developers want to program the same way they do in the browser, everywhere.