It should be a setting to always use encrypted chat, and it should probably prompt you when you first login.

I don't disagree but the claim that you quoted was that it's complicated to initiate and as I explained it's not. Also secret chats stay in the messages list, so you can go back to an initiated secret chat and pick up there without any additional fiddling.

They’ve implemented it in such a way that you only have access to an encrypted chat on a single device, so no syncing between devices. Syncing E2EE chats across devices is more difficult to pull off, but it’s definitely possible and other services do that by default.

its some message for the users, having a secret chat kinda sounds bad, like doing something illegal and guilt trapping users into not using it

But then you couldn't get that juicy user and conversation data.

That's my day job and I'm good at it. People understand when I explain three clicks.

Anything harder than usual in the same application means it won't usually be used.

And encryption is about collective immunity. So everything should be encrypted.

the fact that FB messenger uses Signal protocol, means the encryption is better than the one used in Telegram.

MTProto 2 has not been cracked. MTProto 1 had a weakness and Telegram addressed it. That was many years ago. I'm not aware that MTProto 2 has ever been cracked in all these years. Telegram's unwillingness to cooperate with governments is an additional security layer.