I got Starcraft for my PC when it first came out -- back when there were 3 box designs, one for each race. My CD was stamped "Ver 1.0" and did not have a mac version on it. My girlfriend (now wife) ordered it shortly afterwards for her Mac, and it was stamped "Ver 1.04" and a hybrid CD arrived.
Yes, Blizz has a long history of supporting the Mac, and recent titles have been simultaneously released, but it's not "all past Blizzard games".
Pretty sure it's a moot point.