No such thing as racism, rather, inherent objectivity of the human being.

You posed the question:
"So why do we look at the outward appearance of others at first glance?"

To answer your question:
You HAVE to look at people's outward appearances upon first glance, actually, I would say that it's inevitable? This is simply due to the fact you used the combination of words "first glance." This refers to the idea that you've not only never met the person before, but that you've never seen them either. So, based on that assumption, wouldn't viewing the person in terms of skin color be the only way you can objectify the person without knowing any other prior information about them? It's all in how your mind manifests the existence of other people. You catagorize them because to engage each person individually would probably throw your mind into overload and eventually it would probably explode, considering the fact that 4 billion people inhabit the Earth. But that's besides the point. My point is, is that viewing someone in terms of skin color at first glance is inherent to the human being.