While manipulation of interest rates APPEARS to stimulate the economy in the short term it actually creates malinvestment that destabilizes the economy in the long term. This works to the advantage of the privileged group that controls the manipulation by transferring the wealth of other groups to itself.
Since world central banks cuts the linkage between currencies and gold the manipulation of interest rates has been unfettered. This has caused massive economic instability while at the same time transferring wealth to the privileged class.