Why is it market manipulation if price goes down and then up... Isn't that what markets do?
Because there are a small handful of whales buying or selling large amounts of bitcoin all at once. They do this to move the market one direction or another with the purpose of inducing fomo or panic selling. Then they cash in on stupid/ignorant investors. So the little guy gets hosed again and again.
Obviously, which is why you should only buy dips and only sell after a run. Whales make money tricking others into panic selling for a loss or tricking them to buy after a pump. Basic market psychology.