+1It sounds like your real issue is with ESxx types, then. They tend to drive around even fancier cars than any INxx type, because they regard the car as a status symbol. The INTJs on here seem to be driving their cars because they like some aspect of their engineering, or because they feel like it suits their personality, or something like that.
I have to say, though, I would think that an Fi user would be the first to say that people have a right to do and have things that align with who they are and what they feel, regardless of what others think of them. Instead, you're bringing down the hammer and complaining about their choices being too "feminine," or "gaudy," which is actually a rather shallow judgment to make.
You don't know why they want that car, or seem to care how the car makes them feel. You're just passing judgment because of what YOU think it represents, and how you perceive it, and you think that they should respect that over their own feelings and reasons.
Ironically, I would say that you're condemning shallowness and vanity in a way that makes you look more shallow than the people you're condemning. Your standards are just reversed... you think more highly of people who drive around beaten-up or understated cars, and think poorly of people who drive around ostentatious ones. You're still using the same "shallow" standard as the person who admires ostentatious cars, you're just turning it upside down.