Sure show the Japanese victims, but then you need to show why they were victims in the first place. So you need to show Japanese Imperialism that committed atrocities in Nanking and the attack on Pearl Harbour.
Maybe we could go further and show that Japanese Imperialism was driven by the existential threat of Western Imperialism, which does not in any way lessen the horrors committed by Imperial Japan.
Sometimes the whole story can’t be told in a single film. Not all of it is important to the message or topic the author, director and producers wish to send or examine.