> What do they expect you to do, buy each car, in turn. Return all of them within 7 days. Then re-purchase the one you preferred?

No, they expect you to buy all of them in parallel and return all but the one you want.

I mean, it’s the model lots of people have been using with clothing since online discount retailers with generous return policy started undercutting brick-and-mortar.

There's a big difference in cost and complexity between buying a car online and buying clothing online though, especially if financing is involved (not many people are going to have the cash on hand to float on 2-3 vehicles at any one time).

I can have 7 shirts shipped to my house and they take up a very small footprint. If I'm trying to decide between 7 cars, I'm going to have a hard time finding a place to put all of them, as will most people. That's on top of having to deal with financing multiple cars just to test drive them all.

And as others have pointed out, removing financing from your credit report is not so easy even if you return the car. And I doubt most people would be able to get loans approved for multiple cars at the same time.

buying 3 cars is a little different than t shirts

The implication that the extension of the expectation from online clothing retail to online automobile retail was unreasonable was intended, yes.