why alts prices are linked to btc price?

sample - chainlink price and btc price


sample of price of btc and link:
1 hour ticks

October, 2nd - October 11th

compare price up and down

btc price chart
https://ibb.co/QPXQCj5

link price chart
https://ibb.co/sPq207g

i dont see in description of LINK any info that bind its price to btc - but i see this at picture