Because there isn't anything to meaningfully attack. Chats and chat backups are not encrypted by default.
Shouldn't we have the same standard for all claims?
> Shouldn't we have the same standard for all claims?
Huh? Telegram's protocol has been criticized by cryptographers for making specific "odd" cryptographic choices (see See https://crypto.stackexchange.com/questions/31418/signal-vs-t...). It's not FUD to bring that up.
However, it is FUD to imply something concrete based for vague, indirect reasons.
We either consider the funding of both and decide how the funding COULD ultimately impact the product, or we could look at the source code of the applications and the cryptographic theory supporting them and talk about that. If crypto experts aren't finding holes in Signal's protocols [1], I don't think random people on the internet yelling "bUt It WaS fUnDeD bY ..." will make it less secure.
The problem is entirely that its cryptography was sketchy and just plain weird to begin with. It wasn't wrong, per se, but raised some eyebrows. And then some of the questionable choices were silently fixed removing the ability to MITM, etc, but with no real notice.
It's not FUD.