Nullify means cancel out

To make it clear to you,

>So to climb out of this [cancel each other out], we have to consider how many actors didn't get filled at the price they want. There isn't infinite liquidity at every price point.

And no, there is not enough liquidity, so the price has to move to provide it. That's why you cannot hand wave away price movement, it's intrinsically part of transactions being formed. And why a headline like "Heavily shorted" captures sentiment around a stock, especially one that is tanking.