A contribution to this discussion, I think is of interest, can be found in a recent document published by some registries and registrars (like Amazon, GoDaddy, Tucows), concerning their role (and ICANN's) in DNS blocking. They hope it "will facilitate a productive conversation that moves the multistakeholder community forward towards a shared understanding of DNS Abuse and Website Content Abuse and the roles registrars and registries serve in addressing them." http://www.circleid.com/pdf/Framework_to_Address_Abuse_20191017.pdf