Ah, this would only work if the page was rendered on the server which cannot be assumed of websites these days. If you modify the selector to be "body" and set the output to "html contents of the element", you'll see just a bunch of JavaScript imports is returned.
You'll need a node/library that will browse the site using a remote controlled (often headless/invisible) browser. The remote controlled browser will then parse the JavaScript and render the page as any modern browser.
If you're running Node-RED on a PC or a Mac you might be able to do it with some of the Node-RED contrib nodes I list on this topic: Reset modem through node red
On the other hand, if you're running Node-RED on a Raspberry Pi, I haven't yet come up with a node that would work out of the box, as these browser automation libraries depend on prebuilt browser binaries which tend to not be available for ARM CPU's used by Raspberry Pi's.
