Of course, but the game is more fun for the vast majority of players if it's not required for the vast majority of the skill population. Pro matches focus heavily on micro-heavier caster units and that's fine if it's still fun for the players that don't want to focus on that.
you don't have to micro in starcraft to get fun out of it - but you won't win in a multiplayer match against someone who does. Whether losing due to lack of skill is fun or not will depend on the person.
The single player mode (and custom maps mode) all do not really require micro'ing to be very fun.
