Ask HN: Why is Facebook 2FA enrollment so restrictive?

When I try to set up 2FA for Facebook, I get the message "You must add either a phone or both security key and code generator in order to turn on two-factor authentication." I prefer printed recover codes. They can be read over the phone in an emergency, are harder to loose (if you have a document safe), can be used and understood by anyone, don't break down and cost basically nothing. Phone based 2FA is well known to be open to social engineering attacks, and I don't have a security key because recovery codes. I was able to set up a code generator app factor, but when I afterwards click on Recovery Codes I get "You need to enable Two-factor authentication before you can view your recovery codes." Clicking on the Set Up link again still gives the first message above. So in Facebook world, you must either use known-broken SMS verification, or learn to live with a Universal 2nd Factor (U2F) security key. I just set up 2FA with Google and Dropbox, both of which were happy with the code generator app and recovery code combo. Does anyone else find Facebook's restrictions ridiculous?