You're right, Sunni or Shia don't matter, so you need to learn from your own advice as you are one brought up the sects. Iraqi army is majority Shia and I support them as legitimate security authority of Iraq. There's no reason why these non state militias need to exist. They should join Iraqi army if they have Iraq's interests at heart.
Instead they choose to be seperate entity that challenges Iraqi army much of the time. So I'm waiting for you to give me one reason why they need to exist separately from Iraqi army.
Jordan, Saudi Arabia, Tunisia , Morocco , Kuwait , Qatar all have dealt with ISIS threat without need of non state militias. It can be the same for Iraq too.
So I don't understand your motivations in all of this. Bottom line, these militias should not be praised by forum audience as they serve purpose of securing foreign nations interests.