I'm not sure what point you're trying to make? The people that claim "Telegram is unencrypted" seem to be of the belief that literal plaintext is flying over the air for anyone with a mediocum of knowledge to easily intercept, and that's just not true.
Lacking end-to-end encryption does not mean it lacks any encryption at all, and that point seems to escape most people.
To take it to its logical conclusion you can argue that Signal is also "unencrypted" because it needs to be eventually in order for you to read a message. Ridiculous? Absolutely, but so is the oft-made opine that Telegram is unencrypted.
The difference is that Telegram stores a copy of your chats that they themselves can decrypt for operational reasons. It's up to the user to decide whether the additional functionality that comes with this is worth the risk of a hostile agent successfully requisitioning those chats directly from Telegram themselves, rather than just busting through your door and threatening to break your legs if you don't unlock your phone.
On the other hand, if you fill your Telegram hosted chats with a whole load of benign crap that nobody could possibly care about and actually use the "secret chat bullshit" for your spicier chats then you have plausible deniability baked right in.