"My belief is that the missile was stolen by them from Ukrainian military stocks in Eastern Ukraine, along with much other military hardware, and was fired at what was believed to be a Ukrainian military aircraft. There had been previous Ukraine military aircraft hit by these stolen Buks in the area as well. "
they bragged about stealing ukrainian BUKs, however I tend to believe Russia has delivered them
"A key question is why Malaysian were routing through this area when most other operators had rerouted away from it once these attacks became apparent."
That's the main problem, ATC has rerouted them without any plausible reason (that I could find). Now it's the material for conspiracy theorists...
"Meanwhile, other flights continue between Russia and Ukraine as normal; Moscow to Kiev is one of the busiest air routes in the former Soviet bloc, "
Yupp, just goes to prove how silly that war is.