It ain't human nature.

A man's got to stand up for his own side whatever they does.

That's what it means by Party Politics.

I should 'a' done the same myself if that long-'aired chap 'ad 'a' been a Jap." "But the Japs didn't do cruel, wicked things like that," said Bobbie.
"P'r'aps not," said Perks, cautiously; "still you can't be sure with foreigners.

My own belief is they're all tarred with the same brush." "Then why were you on the side of the Japs ?" Peter asked.
"Well, you see, you must take one side or the other.