Telegram still doesn't encrypt chats end to end (by default¹), which means it's not a strictly superior choice to WhatsApp.
Facebook can't read your WhatsApp messages (of course they can add an update any time to do that), but Telegram has access to all your messages right now.
¹ Yes, you can select the end-to-end encrypted sessions, but they're very crippled from a usability perspective. I don't remember the last time anyone used it with me, yet all my chats on WhatsApp are end-to-end encrypted without anyone doing anything.
Facebook can't read your WhatsApp messages (of course they can add an update any time to do that), but Telegram has access to all your messages right now.
¹ Yes, you can select the end-to-end encrypted sessions, but they're very crippled from a usability perspective. I don't remember the last time anyone used it with me, yet all my chats on WhatsApp are end-to-end encrypted without anyone doing anything.