It isn't a mystery, it's because they think they're a status symbol like going ski-ing.
Except that "everyone" has a SUV these days (not me) and "everyone" goes ski-ing, so it's not really a symbol of wealth/middle classness at all.
What is clear is that if she had been driving a normal sized car the fence/wall/gate would have stopped it and she wouldn't have hit those children.
But that's for a different thread.