I can't tell if it's just uninformed grassroots mistrust of big tech, or the result of astroturf PsyOps to get more people to use the app with weaker encryption.
Encryption is really not the main issue here. I think nerds may not fully grasp Telegram's security model: it's essentially stateless, not tied to any particular country. Its infrastructure is distributed across various jurisdictions, with no official representation in many countries—no subsidiaries, nothing.
As a result, it doesn't respond to authorities because it doesn't have to. However, this approach is unsustainable and unacceptable for many governments, both in the East and the West. That's why he's being accused in France: he is not "cooperating with law enforcement".
Or it could be that he has French citizenship; subject to French law. Spreading your infrastructure across legal jurisdiction doesn't make you stateless - it just ensures you're subject to the laws of each jurisdiction you operate in.
I don't think that's accurate. Like any other business, he collects money from the Western users, so that's one easy choke point. He is also fully accountable to Apple, otherwise he can forget about 1.5 billion Iphone users forever. (apparently, he also just seems to enjoy visiting France and other countries he decided to go against)
He is partially accountable to Apple - he's agreed to a TOS and EULA, as well as conditions for furnishing his Apps. Even with Apple's authoritarian control of their ecosystem though, he isn't fully accountable to Apple. Apple is not a nation or a court that can make decisions like that on their behalf; they have been sued several times for taking punitive action that is illegal obstruction.
Nobody is "fully accountable" to Apple. Apple is fully accountable to the law, and that's that.
he has to disclose his company's location, where they are paying taxes, probably how much money they are making, which makes it far from "stateless, not tied to any particular country". Through that, he also is forced to comply with local laws that Apple plays by, or get kicked out of those countries iPhones', or the App Store entirely. Apple can and does take that action by requests from local governments, e.g. remove a gay dating app from Turkey's app store by the government request.
As a result, it doesn't respond to authorities because it doesn't have to. However, this approach is unsustainable and unacceptable for many governments, both in the East and the West. That's why he's being accused in France: he is not "cooperating with law enforcement".