Earlier quoted context omitted.
True E2E Encryption would also mean the platform(FB, Telegram, Google, Apple, etc.) also can not read the messages and thus the law enforcement can not force them to reveal what a user said because it would be impossible for them to know.
Apple has true E2E encryption with iMessage if you don't turn on iCloud backup of your messages. It's encrypted when it leaves your device and decrypted on the receiving device. Furthermore the messages on your device are locked via passwords from the Secure Enclave.
You and whoever you are messaging of course.