That change only nerfed Adblockers and made Firefox the better supported platform for UBlock Origin but I think they talk about web environment integrety aka DRM for the web, that will break ad blockers enfirely for all sites that want to block them!
Just for the record, ad blockers will still exist despite the changes: https://www.reddit.com/r/uBlockOrigin/comments/x967w5/ubo_minus_mv3/
That change only nerfed Adblockers and made Firefox the better supported platform for UBlock Origin but I think they talk about web environment integrety aka DRM for the web, that will break ad blockers enfirely for all sites that want to block them!