Anyone know what he's alluding to?
>But the loudness won’t be lifted if clipping would be caused in the process
That would have been my first guess, thankfully it isn't the case.
Maybe that's it. Due to its nature, YouTube tends to lend itself to album fragmentation. It's not uncommon for people to have an entire album on their playlist where no two tracks were uploaded together, let alone even share the same uploader.
In this scenario, barring some sort of mitigation strategy, any seamless transitions between tracks would most likely be destroyed. Each track would have been normalized individually.
Maybe he means the fact that if you don't have an adblocker YouTube ads seem to be as loud as the ones on TV used to be. It might be that this will now fall under the aegis of the FCC :) but I'm not really sure about that. Video ads on Youtube are a betrayal of the Google Adwords approach anyway, and the people who gave them the green light should be shot, but with very small calibre bullets so we can keep shooting them over and over until they get the message about how annoying advertising in temporal media is.