UK wanted global access to decrypt any and all Apple users’ iCloud data on request. Apple pulled iCloud encryption from the ADP program instead within UK.

Seems like their idea is to ensure encrypted data outside of UK stays out of UK jurisdiction because the affected feature isn’t available there anymore. But this will prevent UK residents from using iCloud end to end encryption in ADP and keeping for example backups of photos and iMessage logs protected, so for example journalists are a lot more exposed to secret warrants and potential insider threats.