What was the logic behind civil war?

I'm wondering what was the logic behind civil war. Like if Wanda had not made Rumlow fly up into the air then he would have blown up on the ground. If that happened way more people would have died. Cus the ground would have set fire including the bottom of the building that got blown up. And if the bottom was blown up every one inside would have died, So why was Wandy girl so hated on.