I can't speak for gp, but the reason I whitelist Javascript is because the dozens of third party scripts pages load provide no benefits to me as a user and only waste my bandwidth and cpu while risking my security and privacy.
Sometimes the first-party scripts do something useful and I enable them.
That a simple document with embedded videos "needs" js to load at all is sheer lunacy. The modern web is a massive house of cards. I don't want to be uncivil but I find it very hard to understand how anyone thinks they're doing good work after they create a simple (and useful!) web document that requires javascript to load.
If you're using Javascript to make a web application, fine, clearly there's no reasonable alternative. But if you need Javascript to produce a web document, what are you doing? I wonder how much more electricity is being consumed annually processing utterly pointless Javascript.