It might also be given cursory treatment for the simple reason that it was "marginal".

Take France (since i'm french), one of the big users of overseas and colonial troops, the article lists 500k colonial conscripts. Except we had 8 millions conscripts, and 1 million and a half dead soldiers. While their sacrifice mattered and was not honored enough, it's hard to focus on their specific plights, in the end, they represented ~6% of soldiers, and ~6% of casualties. I'm not even talking about the destruction wrecked in northern france.

As always, people feel more about things closer to them, especially when they experienced directly it.