It's not complicated at all. One incident was an active shooter in the process of murdering 12 and injuring 70. The other incident involved no shootings, no one injured, no one killed. In the Aurora incident, the shooter was in a crowded theater in the process of a mass slaughter. In the Rice incident, when the police arrived, he was sitting at a picnic table, alone, with no one in the vicinity, no one nearby dead, or injured. In Aurora, the shooter was inside a building, inside a theater in that building and the police can observe nothing from their cars. In the Rice case he's outside, in a VERY open area, sitting in an open Gazebo, and police can observe all this safely from a long distance away and evaluate the situation, the risk, etc. In Aurora, immediate action was critical because the murders were taking place when they rolled up. In the Rice case, they could take their time and evaluate the situation because no one was shot or injured nor was Rice aiming at or shooting at anyone. He was sitting quietly at a picnic table.
They're as different as two incidents can possibly be and involve a firearm in any way.
Bottom line is if you want to say the guy shouldn't be charged with murder, fine. The cop was an idiot, in way over his head, in a job he wasn't suited for, and his incompetence cost Rice his life. That's an easy civil lawsuit, but I'm not convinced justice is served by charging someone with murder for what appears to be incompetence, and being placed in a position he was emotionally and professionally incapable of handling.
But I don't get you trying to say this incident was handled correctly in any way. If that's the "right" way, then we've got serious problems in this country with an out of control police force with wildly inappropriate rules of engagement with citizens presumed innocent.