I think these days car manufacturers push these SUV vehicles as they are more profitable than smaller cars, so perhaps SUV drivers are more susceptible to advertising and peer pressure.
There is evidence to show that in accidents these vehicles are safer for those in them; but more dangerous for pedestrians and other vehicles. So for those who drive them, perhaps the safety of others is less important than the safety of themselves and their families.
SUVs also use a great deal more base materials in manufacture so hog mineral resources as they hog road space.
And presumably there is more to it than boot space as there are plenty of old-style estate cars with considerably more boot space than a lot of these SUV models.
I think to sum it up, I would say that SUV drivers are more invested in appearances than the average, aren’t really so interested in the safety of others as themselves; don’t really think about the state of the environment too much; and don’t mind taking more than their fair share in life. Vain, gullible, selfish, thoughtless and greedy. There, I said it.