BlazedAndConfused
Alts rise when they either have stellar news, or when BTC goes sideways. When BTC goes on a bull or bear run, alts tank.
Bull run means btc goes up so alts have to go down to basically maintain an equalibrium value of their relative USD to Satoshi levels.
People know this, so they often sell their alts to ‘weather the storm’ of bitcoin going up like a rocket.
They then buy back in cheaper with more buying power. When bitcoin drops, its usually money leaving the market.
Scared money cashes out into tether and other safe haven coins like ETH or LTC. So money, again, leaves.