Interesting question. I can see this but I don't think that power/control and liberation are mutually exclusive in the context of the film. Edward Norton's character is numb, he cannot define himself. Overconsumption, advertising and superficial relationships have left him scrambling to self-help groups that he has nothing to do with. In this sense he feels a loss of control, powerless to feel anything real and lost in a haze of beer commercials and IKEA catalogues. I think, however, that there is a strong sense of liberation. Fight club helped them feel something again. On a primal level, the men feel like men again. The men feel liberated from the endless stream of marketing dibble that attempts to define them. The destruction of these corporations gives them a sense of power and control but also makes them feel liberated from that which once forced them to conform to an illusion.