TL;DR: They all lie, Telegram included. 
I did, and as promised, you have my apologies. This is due to many people showing very unreasonable bias against Telegram, and one I don’t share, simply because people’s stance during those discussions often is:
- I don’t like Telegram because they say stuff I don’t believe.
- I like Whatsapp because they say stuff I believe.
…How is that a good argument, or a factual discussion at all? These arguments inevitably devolve into a belief war, one I am not willing to fight but one I’m very willing to point out and identify that it exists.
I agree with that but I don’t share your faith in Whatsapp / Threema. And it’s only that: faith.
Apple’s iMessages might be end-to-end encrypted – not sure – but their iCloud backups are encrypted with a master key that only Apple has. All it takes is one knock on the door from FBI / CIA / NSA et. al. and they’ll have any chat history they like. The only solution is to turn off iCloud which is only a technical possibility because it’s not a realistic usage scenario for a lot of people.
https://www.reuters.com/article/us-apple-fbi-icloud-exclusive-idUSKBN1ZK1CT
I did some digging on WhatsApp but sadly the 2-3 articles I’ve read about two years ago – that said that WhatsApp provides golden keys to authorities – are no longer around (makes you think about how permanent or unbiased the internet really is… what happened to freedom of speech and acknowledging the dissenting voices?) so we’re left with the official PR fluff pieces which I have no reason to trust blindly. Facebook is really big and has influence. You think they aren’t in bed with authorities? I personally am very sure that they are but, yet again, belief war right? 
I don’t trust US-based companies in general. Even if they have the very best and purest of intentions the justice system there is completely broken. If they want to get your data, they will. A famous example:
Remember Lavabit shutting down because of Snowden? They basically said “we couldn’t do anything legal to prevent the US intelligence agencies getting your data so we prefer to shut down and nuke the data”. What does that say about all US companies? To me it says “if you want privacy, don’t trust anything US-based”. (Although I wonder how can you do that, like 50% of the internet is hosted in AWS anyway. 
)
Additionally, Moxie rejects the idea of LibreSignal using Signal’s servers and branding (says as much on the Wikipedia page). Why not? He only said “federation is not as relevant today as it was a while ago”. Is that a good explanation?
You talk about “sketchy” and “untrustworthy”, I think it’s only fair we include this piece of info in that area as well.
I mean OK, you can think Durov is shady and I am not going to try and refute a belief with another belief (which I don’t hold strongly) but Moxie doesn’t look very good either. Reading through his various statements, he seems hell-bent on promoting privacy (and his own product) while having no problems defending his own territory like every savvy business owner. How much credibility does that take away from him? To me – a lot.
If you like, take a look of the few top comments on this HN thread: Signal’s Moxie Marlinspike calls out Telegram founder Pavel Durov. IMO people bring up an objectively good point relating to a conflict of business interest. It’s worth having the perspective.
Absolutely, I am all for it. But if we judge Telegram, then please factually and beyond any doubt prove that Threema and Whatsapp are doing better. What they say is of no interest to anyone with a critical thinking ability. Of course they’ll claim they are secure. That’s a modern marketing funnel and everybody and their dog is claiming that their products are secure. Empty words.
I never questioned that I want our comms private and I will absolutely never use the completely flawed argument of “I have nothing to hide”. I’m 100% on your side there.
I am only saying that I doubt it that anyone is really actually trying to do it (Telegram included; I am sure they haven’t lost sleep worrying about the privacy of our chats… but then again, nobody is). That’s all really.
OK, I can stand corrected on that but I am 50/50. Not like people haven’t bought green approval badges in the past so I wouldn’t believe anyone saying they were thoroughly audited (and I don’t believe Telegram was as well, for what it’s worth).
I am saying this: transparency gives you some extra points. It doesn’t completely nullify any objections against your product. As an example I cited the previously-broken RSA encryption by NSA. The whole thing was transparent alright, minus one detail that people didn’t think to inspect for a long time.
I never said closed source is better. I am just skeptical if open source really improves things as much as people seem to believe.
Same as we only have the word of Whatsapp and Threema. Let’s judge all fairly and equally.
I probably could have collapsed all my replies into two sentences and probably should have because I’ve spent an exorbitant amount of my Saturday on this discussion (but that’s 100% on me of course):
“Well, it’s only your opinion. Without us being able to look under the hood the whole thing is just ‘my belief is better than yours’ so we can never truly agree during such a discussion.”
In the end, my main goal was not to shill for Telegram. Meh. I have nothing to gain for it. It’s just super convenient for me but I’d have zero qualms ditching it tomorrow if the need calls for it. The truly important people in my life I can reach through multiple comm channels – I am a paranoid techie and I took care of that long ago.
My main point here is: let’s judge everyone equally. And when Telegram is mentioned, many people – you included – seem willing to just believe in other parties’ claims and just take them on their word without any criticism, while inspecting Telegram closely under a looking glass for every single thing they say or publish on their website.
I would like you to recognize that this is not a fair treatment. It smells of negative bias.
Finally, I prefer to think this:
“They are all backdoored and any intelligence agency can get any chat history they want as long as they put the effort for it”.