Earlier quoted context omitted.
Short sellers. People who sell something they don't own, speculating that they will be able to buy it later at a lower price. If so, they make money. If not and the price goes up a bit, some shorts are forced to buy at the higher price to limit their losses. That pushes the price up further, forcing more shorts to buy, etc., causing a "short squeeze" where the price rapidly shoots up very high, "destroying" a lot of…
Pedantically shorting doesn’t have to be borrowing the underlying instrument. Put options are another way to trade on the idea that a stock will go down. I’d actually bet it’s the more common way. It would still be colloquially referred to as being short.
What you described is options trading, one method of which hedges against declines in stock price. Yeah, one could take a "short" position by buying puts, but it can be argued that a short position is not what puts were originally designed for. In contrast to short sellers who obviously intend for the price to go down, or they won't make any money.
I do question whether puts are the "more common way" given that they have an expiration. You can hold on to a short sell as long as you can pay the interest and the loaning party doesn't want their shares back.