P.S. as luck would have it David Glasner just made a new post with exactly this theme, but of course a lot better. Here's an exerpt and a link:
"First, it can’t be emphasized too strongly that low real interest rates are not caused by Fed “intervention” in the market. The Fed can buy up all the Treasuries it wants to, but doing so could not force down interest rates if those low interest rates were inconsistent with expected rates of return on investment and the marginal rate of time preference of households."