Saw this in the tech news today, not really sure if it means anything for Pi-Hole ?
Did some quick research and this article singles out Easylist for including this domain.
This domain exists on 3 other "major" lists.
Any list based upon these lists will contain it.
There is no feasible way they could target all of the small list maintainers. It seems they are mainly picking on Easylist, because it's one of the popular ones.
Additionally, the fact that this has now become news will encourage the masses to manually block that domain anyway.
Easylist is not a default list for Pi-hole, so most users will be unaffected by this specific incident.
The results of this DMCA could cause other ad hosts to do the same. However, this will just cause smaller list maintainers to step up and the domains will still be public knowledge anyway.
In general the effect on Pi-hole is extremely minimal. Pi-hole is a DNS blocking software and does not maintain lists. Pi-hole is capable of blocking more than just advertisements (though that is the main goal). It can block pornography and malicious websites as well.
Not going to lose any sleep over this.