Why not argue that people should be allowed to spend their moeny on whatever they wish?
It's amazing to me how much some Europeans love fascism wrapped up in sheep's clothing...
As an American with a truck (And I'd rather have a car to be honest. I'm getting rid of it soon.) I know how convenient it can be to throw things in the back. I can haul around my own furniture during moves, throw christmas trees in the back, haul engine blocks around, tires, dirty things you dont want inside your car can be hauled there, Tools, ATV's, equipment of various sorts, tents, you name it.
You can try to shoehorn a christmas tree into a Volkswagen if you want, but I'd rather use a truck, and there's a lot of things you don want inside the back of your SUV. Not to mention I dont trust the strength of the floor in an SUV to carry the same kind of weight as the bed of a truck. I've got an assembled smallblock V8 I was ferrying around a while back, and I wouldn't trust that thing's 500 lbs of heft to the floor in an SUV or sedan.
That said, I usually agree with people that they're mostly unnecessary. But when they are necessary they're nice to have. However, most people dont need them, and SUV's are guilty of all the same things trucks are, only they're not as useful. However, I think it's stupid to declare that people should be banned from buying one unless they have a good reason. How would you like it if someone banned you from buying a nice stereo because you didnt need it, or a big tv because you didnt need it? DO you want the government dictating what you can or can't buy?