Though the line may be a fitting representation of the struggles and the hardship of the people who populate that group, the representation of the middle class as a bubble however, itself makes it an object of judgement. The bubble represents the ignorance and apathy of the people within it ,towards the people outside it. It represents a people who isolate themselves to a world within the bubble, and are blind to the world beyond it.
What the bubble does not represent however is that, the same bubble floats dangerously close to the poverty line. The struggle of the middle class, though not as grave as of the impoverished, are still struggles for survival. And the ignorance that most of the middle class is accused of is not ignorance but helplessness.
The bubble that we live in is not blind, It sees the world around, and understands it's struggles. But, is too consumed in its own struggles and is helpless by the weight of it. It is really this helplessness that creates this image of apathy, ignorance and isolation.
The irony is that, an image which acuses the middle class man of ignorance, ignores completely the the problems that he lives with.
The middle class man is sympathetic, but is too busy trying to keep his job. And at the end of the day, he is only rich enough to not be poor.