Except blacks are a race, because they have differences between the rest. You can't put people of the middle east and north africa into a different race than europeans, because they're genetically very similar. Their facial features and skull shapes are more comparitive too Europeans than they're too Asians or Blacks. Skin colour also is an issue, because many Europeans have different skin colours. Some can be as light as paper, while some can be quite dark. Similar thing with the middle east, only a bit darker on average. But this is becoming an argument on biology, so I can assume we're OT now.
Let me clarify.
White people are a race for the sake of Sociological conversation. Because it helps with clasification. But biologically, Arabs, Whites and Slavics are all the same race, but we don't refer to them as such because it makes things harder to comprehend when talking about different groups.
Seeing as this is a sociological topic, saying 'White people' is valid.