That is a shame, but you really can't blame people for being a little peeved about it, (I don't think the author was rubbing his hands together wondering how racist he could be,) But at the same time he should be more aware since popular Manga. (Naruto, Bleach,) have made it a point to diversify the cast quite a bit as well as making them major parts of the cast and somewhat important characters. (When they're not it's more due to shit writing, "poor Chad")
To just say let it slide because it was a mistake isn't very fair to the authors that actually try, point it out and hope he can correct it for next time. Hell a simple color edit for them probably would have made it far less noticeable.
I really do think it was an oversight more than anything. There is, after all, a multi-ethnic group of super soldiers that includes someone from future-china and rather than just being ignorant about other cultures, Japan actually hates China with a passion.
Besides, the bug-people are just an unstoppable karmic force who keep turning out to be more and more cultured and intelligent. The real bad guys are back on earth pulling strings and fucking everyone over.
Although it is regrettable that there are no coloured people among the good guys and it's ok to point that out, a knee-jerk reaction like Village's that just boiled down to him shouting 'you're wrong and I'm right because I have the moral high ground shut up' is just as regrettable.
Just be positive and praise the people who do write a diverse roster of characters. MLK didn't get so far by yelling 'Fuck you', instead he said 'let's work together ands form a positive example and let's cultivate more of those positive examples until we reach the point where it is no longer needed to set an example at all.'