Not sure if you're referring to iCloud [device] backup or all iCloud services. If it's the latter then yes, you can (almost) always choose not to use a service

Not sure if you're referring to iCloud [device] backup or all iCloud services. If it's the latter then yes, you can (almost) always choose not to use a service or website. That's a poor argument to defend bad privacy practices. If it's the former then just disabling iCloud backup does not result in E2E storage of other iCloud data. iCloud photos, drive, etc. are still not E2E.