It is true that Telegram has not always been a good actor in the privacy space, denigrating genuinely secure-by-design platforms like Signal while granting its own users only limited privacy protection. Telegram chats are not fully or always encrypted, which leaves users exposed to both state surveillance and non-state criminals. Wired magazine has documented how the Russian government has been able to track users down for their apparently private Telegram conversations.
Telegram is not a privacy tool