Arch is actually pretty easy to install, both ways (manual and archinstall) have comparable difficulty.
you basically just:

• parition your disks
• run pacstrap (magic utility that just installs everything for you)
• install a bootloader of choice
• create users
• install a desktop environment

I think some people are intentionally making it harder then it seems.
archinstall is completely fine but please read the installer script it runs for you first.
you should always understand what's inside your system and how it's configured if you want to have ability tweak or fix it later.

All the people laughing followed the guide on the wiki anyways. Same thing as an installer script just slower.

:(