“YouTube has provided a statement on the issue … ‘Users who have ad blockers installed may experience suboptimal viewing, regardless of the browser they are using.’
…
This does not completely explain how the five-second delay goes away when using Google Chrome.”
https://www.androidauthority.com/youtube-reportedly-slowing-down-videos-firefox-3387206/
So a slower experience for those who protect themselves from tracking and oops, it affects rival browsers.
How’s this legal, @EU_Commission?