What the digger said was:
Yes, it is true that I am digging and selling my CLAMs for BTC. Though I am not dumping hard. I usually just put asks above the market price. I rarely ever do a market sell order. So although I am adding sell pressure to the price by adding asks to the orderbook, I am not "dumping" technically.
So if you saw "waves of selling" either:
A. Digger isn't telling the truth about not dumping
B. Digger is telling the truth and the dumper was:
1. Unrelated
2. Someone else who figured out the same thing dooglas figured out before he posted it
3. Someone dooglas told about his findings before posting them
4. Dooglas
5. Someone spooked by the increase in above market sell orders.
Even if the digger never did anything other than selling into existing buy orders, the price would still drop. Selling into buy orders removes buy orders from the market without removing sell orders, leaving an imbalance. The price will adjust downwards as new sellers find less attractive buy orders remaining.