> How does an age recommendation take away liberties?

For instance, by being used in further legislation to mandate age verification on all operating systems. Lo and behold, that is already happening - see California.

One can not view a single law and assume it is isolated, when in reality this is a move by lobbyists to further restrict people and sniff after them (see MidnightBSD giving in and adding a daemon that sniffs for user data; I am 100% certain systemd on Linux will follow suit, via a new systemd-sniffy daemon). Some companies pay good money for such legislation. So the answer to your question is very simple, actually. You just should not view it as an isolated way while ignoring everything else - lobbyists are sneaky. It reminds me of Google claiming it has no problem with ad-blockers, then they went on to destroy ublock origin (https://ublockorigin.com/).

I'm skeptical because this is not a new system part of those lobbyist agendas. This is a recommendation system which has been in effect for over 20 years. And this is a tweak to how they update recommendations.