> Quantitative easing is an unconventional monetary policy in which a central bank purchases government securities or other securities from the market in order to increase the money supply
When the central bank 'buys' securities, they do so with money they're creating in that purchase. In effect they're dumping new money into wherever they're buying securities from, but the 'dumping' isn't with dump trucks or dropping it from planes.
Now those bonds come due and the money is supposed to leave the system, but until then the velocity of money means there are knock on effects.
When you put money into the market, but take bonds (which are a guaranteed future cash flow) out you are injecting liquidity temporarily, effectively trading current cash for more future cash.
It's not the same thing as printing money and spending it and suggesting otherwise is either disingenuous or ignorant.
> Quantitative easing is an unconventional monetary policy in which a central bank purchases government securities or other securities from the market in order to increase the money supply