Are you sure about this? I just checked coinmarketcap, and they are saying that the 24-hour trade volume for Bitcoin Cash is somewhere around $2 billion, which happens to be at least four times higher than the net worth of their one million BCH coins. I agree that dumping all those coins at once may be a very bad idea. But it is possible that they could sell at least 25-30K coins per day and complete the process within one month without crashing the exchange rate for BCH?
That 2 billion is churn largely on exchanges that are faking volume still.
It's not the concerted selling of real coins. That's a vast amount of extra selling pressure with no buying back. A whole month of it would flatten BCH completely.
Though I still don't really believe it some say the Gox liquidator selling on market was one of the prime factors in Bitcoin's fall 2018 and that was only about 50,000 coins.