A meme/joke comming from Linux community, and more precisely from Arch Linux community.
Word "Arch" means "Arch Linux", which is a one of the Linux distributions that unlike most user-friendly
operating systems Arch requires you to do a lot of things yourself, including
installation of the system (or you can use "archinstall" command that installs Arch for you). That "do it yourself" part is the key point of the joke as Arch is not meant for casual users, but for those who are willing to learn how linux works and won't rely on system's help.
Think of it like: "I use Arch BTW" = "Look how advanced I am"