But it should be on the GA list, shouldn't be an expection for you.

I believe that's the point of a featured giveaway, the developer personally contacts cg in order to make it so, and judging that this giveaway is up, it means that cg has probably evaluated all the contentions you've mentioned, and still found it acceptable to allow the giveaway, which means the developer has not broken SG rules, except the one regarding the won game on their own account which you can file a user report for.

The difference between giving away one copy of a free game and several copy of free games is that anybody can register to get a game for free in order to give it away, but it is impossible/really difficult to do so when you're planning to give away 100 or 500 of the same game. And it's the developer who's giving away copies of his game, so the question of a free game does not really arise. Plus in this case, the developer won't be farming many levels at all due to the way level scaling works, so it's not an issue.