Well the material in question here is without a doubt not copyrighted by the MPA.

And the safe harbour provision only protects Github from hosting or referring people to infringing material, or material that's "subject to infringing activity" (which is different from what's being claimed here as nyaa is very clearly the object).

That said the DMCA contains all kinds of vague phrases, such as

> linking users to an online location containing [...] infringing activity

whatever the hell that may mean.