Except the first thing you guys immediately say is "well if he didn't have the toy gun, he wouldn't have gotten shot." While this is true, by stressing it you're trying to place the majority of the blame on the kid. By doing that, you're completely disregarding facts like kids playing with toy guns like that every day without getting shot by police. You're trying to emphasize the actions of the victim over the actions of the police officer.
It's incredibly ignorant to say things like "don't be a criminal" or "don't have the toy gun." 99% of the population, you and me included, do legally questionable things every day that could put us in a confrontation with police. And yet when there is an incident that people like me question, the immediate response is a unilateral protection of the police. The victim "obviously was doing something wrong", "you're not a police officer, you can't be questioning their actions!"
The majority of police officers are good people. The problem is, those police officers and their administration do nothing, and in some cases protect, about the bad ones.