Except Telegram has much less E2EE than Signal or Whatsapp.
It's not on by default, works only between 2 devices, they both have to be online at the same time and you can't access anything from the web. And group chats don't support it at all. Private chats are not end to end encrypted by default and it's actually quite clumsy to encrypt them so almost nobody uses it.
It's really weird that Telegram is singled out like this.