He was shot, therefore he is by definition a shooting victim. Saying Brown is a shooting victim does not mean that officer Wilson did something wrong.
He's a victim only in the loosest use of the word's definition. The commonly accepted understanding of the word "victim" is the implication Wilson was wrong with the actions that resulted in Brown's death. But, don't let your bias affect your judgments as much as it affects others!
The store owner was a victim. The officer was a victim of the public reaction. The other store owners of the burned down buildings were victims. The employees of all those businesses burned to the ground were victims.
And what pisses off most people is the avoidance of responsibility. Calling Brown a victim is avoiding responsibility for the damage he cause to others, and avoiding responsibility rioters caused to others. Calling Brown a victim is a way to rationalize their own destructive behaviors.