It is a retort.

Hedge funds do invest in stocks. On what planet are they not investors? They invest.

Short sellers are certainly a bit more ambiguous in how you’d classify them - but at the end of the day they’re still buying and selling stocks, and therefore investing and divesting. Classify them how you wish.

It’s also true that short positions only make up a small amount of the market.

Saying that there’s no such thing as investors or that stock prices aren’t influenced by the buying and selling of stocks is insane. That’s ultimately the only thing that influences them.