Train
Lifer
Letting all your marines shoot any target instead of focusing down one target at a time isn't no macro, it's bad micro. Not feedbacking medivacs and letting your high templars just sit in the group because you did not click anything isn't no macro, it's bad micro.
No, there are THREE options
Good Micro - focus firing the marines to make them more effective
Bad Micro - focus firing them on the wrong things, stimming them when they are already at low health, clicking them to move instead of attack.
No Micro - letting them use their pre-programmed default actions of target selection and firing.