This is exactly backwards. No politician cares about revenue-producing parts of the government; those things take care of themselves. They care about the really spendy parts, preferably those that spend all that money in a few big opaque unauditable chunks. Like the military, or espionage. That way, they know they'll have the leverage they need to make sure large chunks of those chunks eventually get back to them or their PACs.
That's [another, besides GP's] reason why Congress would never choose to chastise NSA.
If what you're saying is true, then it is (dis)provable. There must be ample evidence of what you're talking about, as the votes themselves are public, and resource allocation by geography is (probably) also public information.
I would argue that if you cannot prove it, then you should consider whether or not the assertion is coming more from a negative, cynical sentiment than from any real fact.
These people are unaccountable ghosts; there's nothing to stop them from masquerading as anything from "retail" to "misc manufacturing" to "pharma". But back to your theory. What about "revenue producing" parts of the government (which is what, the IRS?) would cause them to loom larger in a politician's thinking than the sums of money recorded on the linked page?
That's [another, besides GP's] reason why Congress would never choose to chastise NSA.