"Rather than standing and fighting, he called 911 again on the cell phone, making him an easy target for Treyvon.
Perhaps George didn't know how to fight."

Where did you get that information from??? GM didn't call 911 after he was sucker punched and knocked down. It's hard to fight when your laying on your back with somebody sitting on you punching you in the face and head. GZ didn't confront TM, he was just trying to locate him for the cops.