LOL. Here in Australia, we call them thongs - thin, leather strips. And over here, flip flops are ubiquitous. Everyone wears them and there is no such stigma attached. Imagine sweaty, rotting feet in wet socks and shoes steaming throughout the day in hot weather - blech!
Sometime people lack the cognitive capacity to use their intelligence when it is apt. Flip flops are completely relevant in many situations, especially informal ones like making a round to the local grocers. I am pressed to wonder what sick foot fetish these imbeciles nourish to stare at others feet at a store, of all places.