The price and, ultimately, the charts on any given exchange are determined by the price of the most recent transaction. How can the prices of 100s of cryptos all move in the same direction at the same time?
It's because Crypto prices follow a very foolish phenomenon where people or maybe the big traders see BTC as the barometer of the market which means if BTC is bullish rest everything will be bullish and you'll be in a bull run but if BTC is bearish everything will become bearish and you'll be in a bear run. I somehow feel it's because of the great BTC dominance as it still has 40% of the market cap of the total market but it still pretty foolish of all of us to know this and still believe in this.