I have always disagreed with this. What does it teach our children? That it is ok to oppress people. If you win you are king. If you lose you are king. There are no consequences to doing bad things to whole races of people.
It demonstrates that if you're in power and in the wrong, and you do the right thing, you won't necessarily be put against the wall and shot. It doesn't so much teach that there are no consequences to oppressing people as that there are no consequences to
stopping oppressing people.
At the end of WWII, when the Allies were closing in on Germany, the German soldiers fought like devils on the Eastern Front because they knew they could expect no mercy from the Russians. They gladly surrendered on the Western Front because they knew they could expect a nice cup of tea from the British. There's a moral to that.