> Are you saying that Responsible Parents should not get their kids a Steam Deck?

I'm saying Authoritarian Parents should not get their kids a Steam Deck. If the kid can run arbitrary code then they can get a VPN and access websites hosted in Eastern Europe and then any of this is moot because there is no law you can impose on Facebook to do anything about it.

> If a child works out how to circumvent the age restriction and look at boobies (or whatever) and an authority finds out, are the parents liable?

No, because the parents rather than the "authorities" (who TF is that anyway?) should be the ones in charge of the decision whether the kid can look at boobies to begin with.