The app is accused of failure to cooperate with law enforcement over drug trafficking, child sexual content and fraud.
That is, authorities know that that stuff happens on the platform, probably by infiltrating groups, and telegram refused to take actions which would’ve been within their powers to aid in getting a hand on those people. Actions which probably were court-ordered. That, indeed, is being accessory to crimes. I say throw the book at him, lock him up, and confiscate his property as being profits of crimes.
There’s one single way to avoid sending data to police when they have evidence that something criminal is going on: Don’t have that data. Which brings us then to the next topic, and that’s that Telegram is not actually a secure platform.