this is very funny, in my opinion most of the dumper are not those who buy bitcoin at the price of $ 19k but this is a game of price and the market is being manipulated.
everyone has different conditions, so when people sell at a cheap price, there will be a reason. well, maybe you don't have an urgent need so you can still hold the assets you have, and wait for the price to be even higher.
Your right, sometimes, somebody has a reasons why they sell their holding bitcoin, but mostly the reason is to cut the losses, but how about those people who dump their bitcoin just because there are some important thing to go first than to take a losses or benefits in the future.