Well they blocked half of the russian internet while not beeing able to shut it down, i think it plausible they just gave up and made it look like a win. I don't think military groups, secret service orgs and even Isis would be using it if there was any more danger than a bot scraping your group in an attempt to detect keywords. I much rather believe Durows arrest in france might have something to do with wider chanel blocks and deletes. I might be wrong, but i trust my guts on the credo "judge a person [app] by the enemys they make" and Telegram seems to be very high on the hitlist of any organ trying to break user privacy.