The fed doesn't experience risk. It has full control over the size of its balance sheet. There may be other problems with QE4 in the form of Operation Twist II but risk to the Fed isn't one of them.

Also your claim that "the liquidity is not passed on to end consumers" besides being debatable, doesn't answer the claims made by the parent poster. If the Fed so chooses it can prevent yields from rising, which means that the US government will not have higher interest costs.

In sum, the entirety of your argument comes down to the something, something hyperinflation which your heritage link makes explicit. We've heard that story before. There's no reason to think it will be any more accurate this time than it has been for the last 50 years.