I think it's safe to say that what they mean is that: if you win the contest you get the game, regardless of if you backed it or not on kickstarter.
If you win the contest and had also backed the game on kickstarter then they will refund you.
Not that you have to back it to win, just that if you did back it and you win, you will be refunded. (Which is good, don't want people angry that they paid for a game when they won a free copy)
this is rue which makes it a pretty good competition if you ask me