Actually, since money is only "printed" by issuing government debt and because interest rates are still above 0% in the long run they are creating more demand than they create supply. When assets fall cash is king. Markets are pushing up interest rates for both governments, which means they have to sell assets to keep rates in check. They can't afford to let them rise, Japan especially so. That said, I'm holding onto my Yen for at least the next few months. I only buy USD when I need to pay bills.
I'm not sure if you're misunderstanding QE or I am misunderstanding your argument.
When the treasury issues debt almost none of it is bought by traditional buyers (banks and other financial institutions) at this point in time. You have primary dealers who buy the debt when it is issued and then immediately sell it to the fed. The fed doesn't actually have the money to buy this debt so it instead adds credits to the accounts that these primary dealers keep with it. While this isn't actually printing money, most money today isn't printed anyway, it only exists electronically it has the same effect, the money supply increases. Money isn't printed by the issuing of government debt, it is only printed when the fed adds to the accounts of primary dealers, the two are not the same.
When the Fed buys these treasuries from the primary dealers (ie prints money) it has the double effect of reducing the amount of treasuries available for sale on the market. This lowering of supply increases the price which in turn lowers the yield. So not only is the fed monetizing the debt it is also forcing down the rate that the treasury has to pay, regardless of the risk/reward ratio perceived by the market. Currently the 30-year treasury is yielding about 3.3% a year
nominally which means unadjusted for inflation. The real (inflation adjusted) yield on those bonds is much closer to 0%. I'm not sure how familiar you are with zero interest rate policy but that is the trap that Japan has been in for the last 20ish years. Once a government commits to a near 0% interest rate it is almost impossible for them to go back to anything else. debt service payments soon outstrip all tax revenues and even a 1% rise in rates would destroy the government's budget. Thus the central bank has to monetize more and more debt and a vicious cycle is born.
These primary dealers then take this money and have to do something with it, they are profit oriented they cant just sit on this cash. The hope at the federal reserve is that the primary dealers will take this money and invest it in the form of loans which will in turn spur economic growth and lower unemployment. Instead these primary dealers are investing in risk assets (stocks and corporate debt primarily) in order to get some yield off all of the new found cash. Thus we have the risk asset bubble, sponsored by the fed, that will, at some point int he future, come crashing down.
This is why their has not been much inflationary price pressure even though the fed is currently printing $85 billion a month. The money isn't going into circulation, instead it is being used to bid up the price of risk assets. This is exactly what happened during the dotcom and housing bubbles. Easy credit from the fed was invested in risk assets which eventually came tumbling down when the fed was forced to turn of the spigot.
I'm not sure what you mean by they are creating more demand then supply so I cant address that directly. Also what assets have you seen either government sell? their is no need to sell assets when the central bank is perfectly willing to monetize the debt. Interest rates have largely been rang bound since the financial crisis and in the grand scheme of things are significantly lower than they have ever been for this long of a time period. ZIRP is like crack for governments, once you get addicted your hooked for life. While Japan and the US both cant afford to let rates rise that is still compatible with devaluing the currency as I have outlined above. What matters is who is able to devalue faster Japan or the US.