He’s missing the entire structure of QE, isn’t he?
And why is this not repayable? Because QE is money creation. It’s not borrowing. And the end result is new government created money in bank deposit accounts. And if the holder demanded the money back the government would just create new money to make the repayment, meaning that overall no repayment would take place. And that’s why repayment is not, in effect, due.
The money can be cancelled by additional tax due.
And it can be cancelled by new borrowing.
But it can’t be repaid, because it can only be repaid with itself. And that changes nothing.
So, what happens with additional tax? The money is collected and destroyed. OK.
What happens when we reverse QE? The bonds are sold back to the market, the money is collected and destroyed.
Reversing QE is destroying money. Just like higher taxation.