This is absolutely not true and just a myth. Images, video playback, "show more", forms, tabbing, animations, custom icons, hover effects, popups, background images and videos, light/dark mode, hamburger menus...
It's hard to count things you can do with advanced format that is HTML+CSS. Saying JavaScript is nessesary for anything other than block of text is like saying that in Minecraft command blocks are nessesary for anything other than making voxel art.
For basic things like interacting with your bank or goverment, running any additional code should be unnessesary. And I believe this needs to be a law targeting accessibility and compatibility.