Rightly so, it seems very malicious

It escapes from being malicious only because it is very explicit on what it does. But it's very likely that are malicious links to it that hide its destiny.

And it's entirely what ad-blockers should be out to block. So, yes, good thing that it's blocked.

It also seems to be on pi-hole’s list of blocked domains that it uses, as I don’t resolve DNS when I try to access it from behind my pi-hole.

Yeah my pi-hole blocked this one too and after reading the comments here I am glad :)

what ad blocker do you use ?

It seems to be overreaching here as this is definitely not an ad.

By that definition, don't ad blockers overreach these days? (by blocking analytics scripts, etc. too)