That does not bother me because I am sure there were a lot of Japanese who were conscripted into their armed forces and were forced to fight, just like soldiers and sailors in the Third Reich. And the movie did a good job of portraying the Japanese as the bad guys, particularly in the scene of the execution of Bruno Gaido.
A more obvious concession was the inclusion of the Doolittle Raid, which I think was included as a sop to the Chi-coms by showing Chinese people helping Doolittle in his escape. I don't think the sequence was needed to advance the narrative, but I can't complain because I liked the sequence even though it was gratuitous.
There is not much difference in the Japanese conscripting people to go to war and the Chinese conscripting people to work in their factories.
And we often forget just how burtal those Japanese soldiers were.