They acknowledge that piping to bash is controversial in their install guide and they provide other options for installation. I think they were intending for it to be as accessible as possible to non-technical users and piping to bash was the easiest way to make installation a one-line command that requires zero additional knowledge and still works on the tiny raspberry pi zero w. I can't say I agree with it as a general practice but it wasn't enough to turn me off since their software takes like 15 minutes to set up, provides a nice monitoring dashboard, and runs on the raspberry pi I'd relegated to my junk drawer. Your route may be saner to you but it certainly isn't for a lot of people who tinker with raspberry pi and want something like pi-hole but don't have extensive technical knowledge (I am not one of those people I am just a lazy engineer so it works for me too).

https://docs.pi-hole.net/main/basic-install/

Would you feel better with a 3000 line install script inside a package? Or maybe you would prefer the same 3000 lines of code nicely compiled in a single binary?

I'd feel better if the install process didn't rely on manipulating the system package manager using janky scripts. That's a very poor way of handling dependencies, not to mention it's difficult to port.

Run it in a docker container

My assumption here was that you didn’t like some rando script running on your machine with escalated permissions.

I figured running it in a sandbox in a rocker container would be safer to you. Also, it’s easier to get up and running, though more difficult to update.