If the laughable theory that they invited inactives in order to lure them back into the game
If the Alpha is good enough, sure it can lure people back into be Interested in the game. SE already has us no matter what they do from now till release. So why not send Invites to people that haven't played for the longest time, If it's that good enough, those inactives will spread the word and it will be more Believable, than if you had an Active tell other people... they will just think your a fanboi ( as they call it).

I agree with Strall on this one.