@melroy The problem isn't Apple. The UK government is requiring all companies to perform such age checks, and many other places like the EU and California are following suit. Companies - and even open source projects - have to obey the law, even if they or their users disagree with it.
The law doesn't specifically require companies ask for credit cards - and that's a pretty poor way to handle age verification. However, other methods also are bad for their own reasons, requiring users to either submit to a racist and invasive face scan, or provide an ID.

Apple and Microsoft are horrible companies, but for other reasons. Moreover, as we are seeing with California, open source operating systems are also required to comply. Software developers should not and can not simply pick and choose what laws they obey.
Its unfair to blame them for the UK's poorly written mass surveillance and censorship legislation. The blame lies with the UK government, and with every other government mandating this.