While I won't discount your claim about hidden agendas behind much bureaucracy, I don't think you can really apply this to two of my three examples. For ethanol subsidies, sure. But it'll be much more difficult to make the same argument about the War on Drugs or the TSA. In these two cases, how is money being funneled to powerful political stakeholders?

Police departments and corrections officers of all types. The TSA is a giant jobs program for workers no one else will hire, and the body scanners are produced by a company owned by the Secretary of Homeland Security that mandated their purchase.

Good answer. Do you think it's always the case, then, that any governmental program automatically creates its own constituency?