It's as simple as the abundance of supply of bitcoin in the market makes the prices go down.
FUD's doesn't affect the price directly but this could influence hodlers/ investors into selling their coins and add more supply in the market.
In my own opinion, FUD is the main reason why the market prices are dumping in the market but we can still consider for some influence because there are also crypto analyst who are creating negative speculations about bitcoins and altcoins.