I didn't realise there was a correct way to use Arch, or that there were people authorised to explain what it is. Is that an Arch-exclusive service, or is it available for other distros as well?
You say the whole point is ending up with a system configured the user's way instead of some celebrity's way, and then you go on to tell us what we are actually allowed to want. That's a bit rich.
Starting from someone else's config and then changing whatever annoys you is making the choice, it just skips the part where you spend a weekend reading about display managers to arrive at the same place. That is what dotfiles have been for since roughly forever.
By your standard, anyone who used archinstall from the official ISO isn't really using Arch either, and I suppose the truly enlightened path is Linux From Scratch, compiled this morning, on hardware you soldered yourself.