This has nothing to do with privacy either. First of all Telegram is not a private messenger. Secondly, this is a about public forums and groups called Channels. This has nothing to do with backdoors eithe. They are simply asking them to do moderation on chats they already have access too.
Telegram has full access to this data and knowingly ignores child pornography and other criminal activity. If Facebook did such a thing for years you’d be screaming right now.