[icebraining]

Why do you assume the roof rack is part of the rented car? You can just buy a rack and put it on the rented car.

[unwind]

That's true, of course. And they do list the rack in the list of materials.

I mis-interpreted "If the car doesn’t come with one, rent or buy the specific roof-rack for that car", which still mentions renting the rack as a solution, of course, even if it seems they actually didn't rent the rack they used.