If he did it it in the course of the robbery I would support him.
If he made a choice to go racing through the streets because his money was more important than anyone elses life then I would not.
I find it humorous that people supporting a vigilante are upset with the idea they might have to face the consequences of their choice.
Once again you support what you complain about, vigilante justice. You feel it is OK for you to get revenge. But not OK for the store owner to follow the perps and then respond to thier actions.