That wasn't supposed to be sarcastic at all.
I was in total agreement with him - you can in theory run the algorithm by hand.
It isn't especially relevant though - 2-factor is "something you know, something you have". You need to have the hash.
In fact, in Google Authenticator you can even conveniently export all running TOTP to another Google Authenticator without any connection with the apps or anything else whatsoever.