Sometimes many people try to manipulate the market and buy precious tokens cheap and selling high later.
Those people who are selling high and buying at cheap prices are traders and that isn't manipulation. But this can be called manipulation if there are traders that we call whales.
They intentionally cause fear and panic in the inexperienced members and take advantage to perpetrate their greed activities.
With the help of FUDs they really cause panic to those inexperienced investors who doesn't have an idea on what they are investing.