Is it bad that I'm going to tell a woman not to buy a car?
Why do you want to do that?
Because cars are expensive and women shouldn't spend their money on cars, they should spend it on home needs.
You're a sexist. Women can buy whatever they want. You have no right tell her that she shouldn't buy a car.
That's not true, I think women can do whatever they want, but that does not mean they should.
She earned the money and she can make her own decisions about how to spend it. You have no right to tell her otherwise.