I am not invested with the authority to deem that some academic economists are engaged in true research while other are merely propagandizing. Some academically trained economists, including the gentlemen you mention, do indeed explain away the business cycle. (As you point out, it is mostly by claiming it is inevitable but self-curing.)
Lord Keynes is all very well, but Friedrich Hayek is certainly highly esteemed. Order of the Companion of Honour, I think, plus a Nobel Laureate. His disciple, Margaret Thatcher, was just awrdeded a lavish state funeral for her success in championing his ideas. And there was nearly universal condemnation in official media of anyone so vile as to disapprobate her Hayekian triumphs. Government is the problem, and capitalism is the cure!
I can understand why you want to think of only what you can accept as honest attempts at science as constituting the profession of economics. But in the world as it is, isn't that really just wishful thinking?