Just to understand, I do not see the possibility of short selling on exchanges...
There are many people who can do that, any trader can make money from a dump coin. It is important, they have enough brains to decide when to buy and sell it. It is difficult to make the best profit when trading.
If trader has enough brain he can. You could find lots of examples for that. The most important thing is to sell or buy at best time, that's all.