I get that. American middle class is hurting, but looking at the world as a whole. they all collectively make up the world's 1%. So going from world's richest 1% down to world's richest 2% does not affect the global poverty average that much.
Of course, it makes the case for "the worlds is getting better" harder to make. Also, it's an indicator that there are some problems the US (Europe also, in somewhat similar situation) that we should probably be addressing.