If all the neighborhoods where green people live.. have a higher crime rate and higher risk of $badthing, am I being racist against green people? I don't think so.
The first point is that racists seldom believe that they're being racist. Because that would be irrational and they all have very rational (to them) reasons for believing whatever they believe.
The second point is that you would be basing your opinion upon a visual characteristic when the real reason might be something you cannot see. Such as economics. Bad neighborhoods have low property values. So poor people live in bad neighborhoods. Not because they're bad people but because that is what they can afford.
Maybe when I'm in the good side of town, I see a green person and I greet them normally.
Maybe. But if you're aware that you're greeting him "normally" then you're probably a racist.
When I see an old Chinese woman walking her poodle on the street I treat her the same as I would any other person who was not ...