I wouldnt say its a "rule" they're having here - its a courtesy and they're telling you "We are going to do this ONCE for you. We're going to dig into our data once to get something back you throw away."
They wouldnt even have to do this and its not a feature that should be treated lightly - depending on when you created the character it might get into conflicts with names, its taking away time for that guy who's doing the restore, restores arent always easy and smooth etc.

I fully understand that someone can do something like this in a very emotional situation, I've seen it happen. But, personally - and this might sound a bit drastic here, bare with me, please - there have been times when deleting my character would have felt like a "mini"-suicide. And when I felt tempeted to delete my character I stayed away from the game. And its the best advice I can give anyone - if you feel the urge to delete your character, step away, clear your head, come back tomorrow and see if you still want to or if you cant just walk away. Dont do stuff like this an expect a company like SE to pick up your pieces for you... So, no, I dont feel like anything needs to be done here - unless on the side of the people deleting their characters multiple times.
Dont kill your character if you dont want them to stay dead...