Telegram can read all your text mesasges, unless you specifically setup an encrypted one-on-one channel between users that’s tied to a specific device, so basically nobody is using that. It does not have to actively siphon the conversations to a state actor, an exploit chain or the good old infiltration by a rogue employee is enough.

Disclaimer: I use telegram, but have zero expectations of privacy there.

It also wouldn’t be the first time the russian government is using an organization for their own agenda abroad, while banning it in russia.