Batman (badly mischaracterized by writer Joe Kelly) states that to attack a sovereign country without UN authorization would violate international law. Completely out of character. Batman has violated international law numerous times. Hell, he once left the Justice League specifically over their refusal to let him violate International law (which led to the creation of the Outsiders).
You're right; completely out of character for Batman. The whole time I was reading it I was thinking, "What IS this??"