Wall-E is truly a gem of a movie. I saw it with my wife and three boys (all under 9 years old) and we all enjoyed it immensely.
With respect to BnL, and talking messages/themes here, you have to understand something - BnL is the *only* entity shown ever. This implies not crass commercialism, but absolutely monopoly over business, economics, and even government. With no competition, you have no Capitalism, and thus any statement attempted to be made concerning Capitalism becomes, in fact, a very accurate statement concerning Communism. From this perspective, a lot more becomes clear - the similarity of all the humans in what they do, wear, and "eat", even their slovenly nature from a life of invariance and lack of effort.
Wall-E is, whether by design or accident, a movie with an absolutely excellent message - one of what it means to be human, the strength of the human spirit in its individuality, and the appreciation of life that we're all capable of when allowed (taking the blinders off) to see things as they are. That it takes a lovable little sentient robot to show these people how to be human is part of the charm of the movie.