And I would rather have the _choice_ whether to prove my age to Apple or not. I think if it were optional, with the additional option of "share my age with websites & apps", nobody would have an issue with it.
It is optional, you can skip past it. Presumably you will lose access to some websites and apps though.
The issue is that if you don’t prove your age, access is blocked.
So it’s not optional. At least in Australia.