What does mean: "someone re-raffled a game"?

Means regifting what they've won

If you win a game, you need to activate it on your steam account. If you don't do that and re-raffle the game you won ( make a giveaway for the game you won ) you break a rule

1. person wins game from steamgifts
2. person needs to add game to his steam account, but does not
3. person takes game he won and makes a new raffle (sometimes person "gives" game to someone else or trades game on the trade market)

OK, thanks for your very clear explanations!