You are coming from a premise that the color of one's car is somehow a basic human right. In the last 75 years or so American's have evolved into a species that considers their car an aspect of their personality rather than a mechanism for transport. The car has become glorified through idiotic car commercials, car magazines, a 'sport' (NASCAR) etc... etc... Now that we are starting to see the devastating effects on the environment from the overuse and misuse of cars, Americans are faced with a choice: a) give up or modify their status symbols and toys, or b) give up their right to breathe clean air. This is not a liberal idea, although it may be a 'progressive' one. It seems to me a sign of maturity to give up the infantile idea that your car expresses some aspect of your personality, unless you are someone with no personality...
FYI- the car I drive is a white Nissan X-Terra, which I bought because I need to transport equipment as part of my job. Most of the year when the weather is nice however- I ride a bicycle to work...
I do not derive any personal sense of identity from my vehicle- I bought it because my dad works for Nissan and it represented the best deal I could get and it scored high in reliability and gas milage.