If they sell at a lower market price, they incur losses. They are assholes. At the same time, other guys (holders) are forced to experience discomfort.
Therefore, now some projects are listed on the exchanges not immediately after the ICO, but when the finished product is released, so that there is a need for tokens and their price is higher.
But such case is not good for bounty hunters. They have to wait when product will be launched and it must take a years.