when YOU are trading in the market then you are a part of the market. if they control YOU then they control the market. the real question is how many of these YOUs they affect when the dumping happens. and the answer is that it changes based on different times and the market status.

for example at the beginning of the year when bitcoin was still in super hyped up mode we had a lot of these YOUs who we call "weak hands", when the correction hit they panicked and sold. or when the whale dumping during the $10k fiasco started they again panic sold their bitcoins.
but they will always go out and the market becomes void of them. for instance when the $6k dumping happened 3 times so far this year there were not that many weak hands to panic sell so the whale dumps failed to push the price any lower and they lost money since they were forced to buy back at higher prices instead.