I mean the basic logic of the service was designed somewhere before its release. Data policies, promises to users are nothing if you assume services should adapt to stuff like this, at the expense of breaking those policies and promises.
Here is an old article from telegram about reasons for how it works https://telegra.ph/Why-Isnt-Telegram-End-to-End-Encrypted-by-Default-08-14
That one was hardly legal, not sure about “safe”.