ok, this is what a player just posted on my forum,
http://www.bonusparadise.com/forum/freebies-free-tourneys-no-deposit-bonuses/5210-vegaspartner-christmas-calendar.html#post25359
I just got this from Vegas Partner:
We have confirmed with the management team that the game My Slots should be on the Games Lobby page for USA Players. What you will need to do is please write down the time that the game was not showing on the software and please add all details so that when we contact Microgaming we will be able to give them the information they will require and get the issue resolved as soon as possible. Micorgaming will give us further information regarding the My Slot game for US players.
Vegas Partner Lounge
Wow, so it seems it was by error!?