Usually, if animals look alike, they can be categorized into the same group. But if you categorize human in the same way, you would at high risk to make mistakes.
Why?
It is because human can be largely consciously controlled. And the consciously controlling part can be developed into very different characteristics. And individually, it has nothing to do with their appearance. (Probably there is difference between groups because of genetic difference. But it isn’t the case individually.)
So, when we categorize human, we should learn their values, conducts, reasons, how they response, their experiences, desires, knowledge, the way of thinking, the way of solving conflicts, how they control themselves, how they consider different parties’ interests, the feelings they experience when they are in some case, their pursuits, their personal history, … If we categorize human in that way, we would at lower risk than we categorize human because of their appearance.
Discussions on the Han Chinese Mental Illness 