There is no system, there are just people. And is it justified to hurt people over theft? Of course it is.

All legality ends in killing when taken to its end result. If you get a speeding ticket, what happens if you don't pay it? You get a warrant for your arrest. What happens when you're stopped for speeding again and the officer, noticing your warrant, goes to arrest you but you, believing the state has no business apprehending you for something you never agreed not to do on roads nobody actually owns (which is a legitimate and objective claim, mind you), resist that arrest?

One of three things can occur:

1. You are arrested, which means that another human being placed their hands upon you and did things to you that you do not consent to. If your neighbor did this to you you would consider it both insane and immoral, and you would be wholly justified in that consideration.
2. You escape arrest, but you will most likely be arrested in the future.
3. Your resistance utilized some level of force which was reciprocated by the officer, and you were shot and killed.

And what do you think happens if you do successfully resist arrest? Now you have a warrant for your arrest not only for speeding, but also for resisting arrest. And what do you think would happen if say, you successfully resisted arrest say, 5 times? Do you think the state is going to just throw its hands up and say, "well, we tried but that bugger got away so what can we do!?" No, of course not. Eventually the criminal escalation will be so great that you would be seen as a violator of the law wholly need of processing, which means violence used against you to ensure your capture. What happens then when those escalated officers draw weapons on you and demand your surrender and you try to escape a sixth time? They throw up their hands?

Of course not, they open fire.

ALL criminal acts eventually lead to death unless you succumb to the will of the authoritarian structure or you're successfully captured and processed, it just depends where along that line you are.

Is it rationally justified to open fire on someone for stealing from a Walmart? Of course not. But it would have been justified to arrest the woman and punish her to the fullest extent of the law, barring that the law is just, and by just, keep in mind, simply being that in which violates the will of another through a logical order of operations. I.E: Murder, rape, theft, fraud, etc.

An officer who shoots at a car to prevent someone from getting away with petty theft at a Walmart should be tried and convicted of murder, but the woman who stole from that Walmart should be tried and convicted of theft, at least barring that the Walmart wanted to press charges at all.