Why Survivng Mars Deluxe is still available for a giveaway?

It was marked as double ** wich says who give this game will not receive any CV from it.
50 min remaining to get it FREE
Edit: the second one i suppose you can create a support thread wich allows you to mark "request received feedback"

1) those are useful for people who can't have a HB account (or don't want to link their Steam account to HB, since HB made this mandatory to claim their "give"aways)

2) I think you need to create a support ticket for that, with the reason "request received feedback" (and then explain as accurately as you can, maybe a few screenshot may help as well). And then be prepared to wait, support tickets tend to take a loooong time.
You can know if a winner revealed the key if they have a green eye icon next to the key (see your previous winners for an example)

2. File a support ticket for "Request Received Feedback"
   When it's done bl the winner.

cause i dont look at what i join just clicking join

what?! o.0

Free games was allowed a ways back, but they do not give CV to the GA creator. Like Almada said earlier, such games are marked with dual asterisks. If it is a newly free-released game the asterisks might be missing, and the GA creator does get CV - but as soon as the SG database is updated any such CV earned is revoked automatically (IF the GA was created after the date/time game was released as free).

When you look at your own giveaways (Giveaways/View Created) there's a link in the column to the left: Winners.
Click it and your winner(s) are listed there and next to the key there's a little eye displayed if they have viewed the key. It is not displayed if they have not viewed the key.