What exactly are you taking about? Many (most?) Bitcoin holders are the opposite of this… they never sell. Haven’t you seen all the statistics about the amount of coins that haven’t moved in one year plus?
He/she did say "Bitcoin traders", not investors. The investors, who never sell, don't affect the price.
I've always wondered why, with a $1tn market cap, it behaves more like a penny stock, and this might say something about the type of people actively trading it.

