I think you meant to say that you don't actually need a Pi. It's unfortunate that they named it that way. Never name things after the technology involved in making them work, because if your thing is any good, it'll spread to other devices/languages/operating systems.

Maybe they found the name to be funny?

You're right, I've corrected.

Can you recommend a guide for setting it up on something like a mac?

I dont know much about macs, but googling this looks like it should work for you. https://pawelurbanek.com/pihole-local-computer, though I'd try to use the official compose instead of his version on github. https://github.com/pi-hole/docker-pi-hole