This is a false assumption, because some people definitely are. What is the real point of your statement? That you are not interested in opinions of such people?
Sure. You shouldn't care about the opinion of anyone who cares what car you drive, because they are, as made clear by that opinion, entirely superficial thinkers.
There's a comment higher from here that expensive car is a good proxy signal of wealth. Preferring wealthy people may feel unjust and even obnoxious, but it is definitely not superficial thinking. I personally would too steer clear (pun intended) of people like that, but just discounting them looks like the same behavior, isn't it?
At least where I live, what car you drive has mostly come decorrelated with wealth. Obviously at the extremes there’s still a relation (the guy with the beat-up 1990 civic is probably not rich, the girl with the $120k AMG wagon is), but is a new Tesla 3 driver richer than the person with a 2005 Subaru Outback? Who knows!