Can we find an act of rebellion in Andy Warhol's art?

We can find rebellion in Warhol's art beginning with his renderings of common supermarket items, Coca-Cola and Campbells Soup. Similar to Duchamps readymades, taking commonplace items and interpreting them as objects of art, Warhol takes items a general audience is familiar with and makes them art. But how is this a rebellion? It can be viewed as social commentary on the nature of consumerism. While Duchamps readymades were domestic objects of function, Warhol chose items with a trademark value, rebelling against the consumer obsession with name brand items by throwing it in their faces in repitition.

Are pieces like Empire, or I, a Man challenge the viewer, rebelling against how people perceive art in its environment?

I think that they do. The former is a n 8 hour piece that in ways simulates a single angle lens view of something, in this case the Empire State Building, but because there is a dimensional time scale assocaited with it, one has to watch it for the full 8 hours to take in the work in its entirity, defeating those viewers who spend far less time on an art piece. Perhaps it is a statement that no amount of time can be enough to fathom art, or that any mundane image in art has the power to hypnotize and entrance the viewer.