Because a court interpreted the law and ordered them to. And protecting companies from unlawful piracy is just as much a moral good as protecting the consumer from ransomware and threat actors. And if the DNS company can do the one, they can do the other.
It is not obvious that any specific unauthorized act of copying is "piracy," there is always a fair use argument and at the end of the day it is up to the courts to determine whether or not fair use applies.
Pretty inconvenient with the Internet being a thing.