Not all altcoins but I think Bitcoin is fully manipulated, whales are the one who manipulated bitcoin price, one factors that could manipulated crypto coin is the news and other articles about the coin and the community if the team or developers are active in endorsing their project.
As soon as Bitcoin is manipulated mostly by the whales, it affects the price of the altcoins. when BTC price is going up, the alts are gaining and vice versa.