Is there some suggestion that these obviously wrong examples are intentionally ahistorical or intended to erase history? Is this a plot of some kind? How common are these issues relative to all the other images being produced? Apparently the tool seems to be reluctant to produce images of white people at all. What should the appropriate frequency of white people be? That last one is a serious question that should be answered with an actual number, because that is the central concern here (unless I'm mistaken).
What seems very likely to me, is that in an attempt to not make the tool embarrassingly only produce images of white people they overshot. Bear in mind for a second, that for anybody who isn't white and is trying to generate an image of a person doing a thing (with no historical context to infer a race for that person) it would possibly be deeply frustrating to only get images of white people.