Using https would already mean encryption is not off by default. There are so many layers that can be encrypted. But at the end data is stored somewhere, and the keys must be available to the infrastructure to decrypt and serve the content.

Maybe the parent content meant E2E is off by default, which is what your first link states:

> Secret chats use end-to-end encryption, thanks to which we don't have any data to disclose.

Then the next paragraphs elaborate about the non-E2E encryption, and how would it be harder —- while not impossible —- to disclose data.

From the same link you shared:

> Thanks to this structure, we can ensure that no single government or block of like-minded countries can intrude on people's privacy and freedom of expression. Telegram can be forced to give up data only if an issue is grave and universal enough to pass the scrutiny of several different legal systems around the world.

Maybe getting the CEO of the company arrested is what it gets to disclose that data they want. After all he controls infrastructure and deployments.

Meanwhile, unlike Telegram, everything in Signal is E2E by default[1].

1: https://signal.org/bigbrother/santa-clara-county/

Encryption between you and the service provider isn't encryption protecting you from the service provider. No end-to-end encryption means no encryption for messaging.

The only context where client-server encryption matters is when I want secure e-commerce, or to shield from my ISP what searches I make or what I do on sites.

Well, they are "encrypted", but not end-to-end encrypted. Encryption does not really mean much if someone else has the keys. So it is reasonable to treat non-secret chat messages as if they were unencrypted.