On the surface the argument might seem strong, but allowing the train of logic presented run further would create a paradox.
What would be necessary to prevent all murders and crime? Would it not involve stopping the humans who were performing them?
Recall the 2002 film Minority Report about a police force that apprehends criminals based on a foreknowledge of events. Something of that sort would have to go on, either by divine means or via humans or perhaps something we have no knowledge of at present, correct?
When you stop a crime based on foreknowledge what do you do with the person who was going to commit it? Do you charge them? Do you jail them? If the person was going to commit murder, do you execute them? That means we would live in a state where people get charged, jailed, and likely executed for crimes they never commit. Is that what you are proposing? Where's the justice in that?
What if I stopped you from being able to reply to my post here? Let's say that I had foreknowledge of what you were about to write, and I did not approve of it, and that I also had the power to stop you from doing anything I didn't want you to do. Would you say you had real freedom? Are you saying you would only believe in God if this was the paradigm, if God dealt with you and others like that?
If you choose to not believe in God, did that happen because God doesn't want you to believe or because you have the freedom to not believe in God? If God is all-powerful, why doesn't he just prevent all people from not believing in him? Why doesn't God force us to believe?
And if granting freedom makes God bloodguilty of the crimes God does not commit, what does it put the humans who commit the murder? Does that automatically free them from being responsible? What if there is no God? Are we as a society to allow criminals to run free because there is no God to stop them or to prove that God doesn't exist by allowing them to run rampant and thus have something to point at to say: "Ah-hah! See? The is no God!"?
It's a paradox. There's no front without a back. Light only exists because there is darkness to compare it to. There is freedom and there is the lack of freedom. There is good and there is evil. Even without a God, who is responsible for the crimes and murders? Who would non-theists blame?
If you do not believe in a God, then you cannot say you do not believe in God because he is bloodguilty for crimes of humanity. Where God doesn't exist there is no blame to place on someone that isn't there.
One last point to consider: You know there will be injustices committed today and tomorrow and beyond. How can you prove to those who charge you that you have done everything in your power to prevent these evils or that you were without power to prevent this or that injustice? Are you so sure? Can we prove that an action we do or fail to do does not result in an injustice, a crime, or even in a murder tomorrow and that we are thus not bloodguilty? Are any of us truly powerless to prevent the evils of society today or completely innocent of any contribution to such things by our actions or inactions?