The problem of pain and suffering and death (whether of human responsibility or "natural") is immense. If there is no complete, final, adequate and satisfactory (just) answer to this problem, then we have every right to be very angry with God indeed: not that this would do us any good.
Of course, it is God who has made us how we are and has given us an awareness of the rights we have, as beings created in the Divine Image. It is God who has enabled us to appreciate the horror that is wickedness. It is God who has constituted us with feelings of righteous anger and a hunger and thirst for righteousness. God very much wants us to be aggrieved about the injustice which flourishes, even though we cannot fundamentally solve the problem in this world.
"Blessed are those that hunger and thirst for righteousness: for they shall be satisfied."