I think what was stated is that you get 2.5 free votes a day. (that's how the regeneration works.)

Pretty sure it is working as designed.
Destroy an account seems like a dramatic way to put it, while you could downvote 12 times on one account you would have nothing left in the next days, meaning the account wouldn't be destroyed at all. Rather it would have to have enough open items to have rewards on 12 posts or comments to remove. Once that hit was over there wouldn't be much more the overly zealous downvoter could do.