Not being end-to-end encrypted is meaningless to law enforcement if Telegram refuses to turn over the chat contents (which they do). Law enforcement can't just eavesdrop on the conversation without Telegram's cooperation. The chat contents are still secured by TLS from the user's device to the Telegram servers.
Smart professional criminals rarely use Telegram for this stuff anyway. There's WhatsApp and plenty of other popular platforms of end-to-end encrypted
if Telegram refuses to turn over the chat contents (which they do)
Source?
Law enforcement can't just eavesdrop on the conversation without Telegram's cooperation
Why do you think Roskomnadzor gave up their blockage plans in 2018? And then made their own official government channels? "It's technically difficult for us" has never stopped Roskomnadzor before.
It's not just "technically difficult" to eavesdrop. Properly implemented, it's computationally impossible to eavesdrop on a connection secured with TLS.
There's nothing in the article that says they refuse to disclose chat contents. In my own experience they often do so when receiving a proper request from governments, providing at least the last 24 hours of messages.
My comment regarding Roskomnadzor has nothing to do with encryption, but rather Telegram cooperates with them, and that's why they stopped trying to block the platform. A little bit of reading comprehension would do you wonders.
The algorithm for the end to end encryption is open source as far as I know. Should be easy for security researchers to prove that something is manipulated...
I'm calling the E2E algirithm open source. That's the reason why WhatsApp is using it, too. As long as the message is correctly encrypted for E2E on the client side, it should not matter what the server is doing as far as I know.
Three of these have existed for multiple years and have not been asked to stop development. The gurk-rs dev even commented (on reddit, unfortunately I can't find the source) that it reports to Signal's server as a non-official client and that if the Signal devs wanted to block it, they could easily do so.