Earlier quoted context omitted.
I think it should started a discussion about some excesses of the stock market. Rich people can look for battered companies and severely profit from their accelerated demise which some people wanted to fight against for once. Out of their own motives for profit or just for fun to be able to at least once stick it to speculators looking for easy profit. That trading was halted and "corrected" proved they had an impact…
The purpose of stock markets is to find the "correct" price for a stock. To that end, it needs to be possible to express both bullish and bearish views. However, doing the latter is already more difficult because in order to short the stock, you need to borrow it first, and you need to pay for those borrowed shares for as long as you keep holding them. Furthermore, those borrows can be pulled at any time, forcing you…
For example: you can't go to the bakery, borrow a loaf of bread, sell it to a passing punter, and then pay the baker at 5pm when they drop the price to get rid of their stock before it goes stale.
The rest of the economy manages to find the "correct" price for things without shorts. So could the stock market.