According to achow101, theymos made it this way so that when someone (probably a hacker) tried to guess the secret questions using the leaked database from 2015 (you know which), the account gets locked. This was probably a failsafe or a precaution to prevent anyone from guessing the secret questions from the old database

Check the link I have provided, your "why" is answered there.
I know why this block occurs when someone tries to recover the password using this method. I just think that instead of adopting the blocking model, the model of making it impossible to use this method could be adopted.
Honestly, I even thought that this method had already been removed from the password recovery options. It makes no sense for him to remain active.