To "clickbait" poor person with luxury car is easier than rich person.

It is not a bad thing because in the end yes, will be discriminated at the counter by amount of money they have. Of course no one should get stuff for free.

It is bad in general, because people will be closed by their socioeconomic status and will have less possibilities to see better things. It can reduce economic mobility by some business not wanting to deal with people who are classified by automatic classifiers, even though they might have more money, be smarter, than what their FB history is telling.

> It does not make sense to market luxury cars to the poor,

Luxury cars aren't the concern. It's tumbrels we're worried about.

It's a good thing for business, yes, but there are a lot of ethical implications surrounding socioeconomic/behavioural predictions. I've been getting the feeling recently that Facebook has successfully circumvented decades of regulation on human studies since their research isn't (correct me if I'm wrong) governed by the Institutional Review Board