The text is saying that only secret chats offer end 2 end encryption. With e2e encryption the message can only be read by the original sender and the receiver

The text is saying that only secret chats offer end 2 end encryption. With e2e encryption the message can only be read by the original sender and the receiver specified by the sender. The quality of the text is btw very questionable and dubious as e2e encryption has nothing todo with where the message is stored. See email where your gpg encrypted message is stored on a lot of systems on its way to reach its final destination. This text makes me distrust Telegram even more, thank you for sharing this!