When you say JS is enabled for each domain a page loads, Can you clear what you really mean?? Does not that mean what that video showed??

Please do me one favor, when you load a webpage, please go to web console in firefox and paste this

var resources = window.performance.getEntriesByType("resource");
resources.forEach(function (resource) {
console.log(resource.name);
});

and tell me is the output that comes, you mean that by external domains it loads, kindly confirm