Do you know what's the beauty of fiat money printing? Value doesn't come from a printer (unless you're selling books), so no matter how much they print, the total value can't go up!
And do you know what's the hanky-panky part of fiat money? That what you said is an illusion in the short term.
Yes, in the long term you can't “print” value as the new money will enter the circulation and prices will rise due to supply & demand, but until they enter the market (which is the short term), they are regular, non-changed-in-value money. So, if they printed/added another billion dollars in their bank balance, they could accumulate more BTC which would obviously rise the price.
So while the total value can't go up, they can deceive the exchange by trading a currency that is guaranteed to lose value afterwards.