Telegram sends activation code to known devices, no sms (and I don't remember when it happened, maybe 4 years ago, probably for all other competitors). Also creators of telegram told everyone to use secret chats if conversations are secret to ensure p2p and forward secrecy. And to check key fingerprints to identify peers.
As usual, security threads consist of ancient beliefs, non-users and stories of low-conscious people using high-tech software. And there is always someone who mentions whatsapp as an alternative. Things like wickr are not even mentioned here.
