Developers don't think you enjoy using the terminal. It's just the option that works with the most systems with the least explanation. They can just give you a command to copy/paste instead of a tutorial on what buttons to click, assuming you even have that.

There are GUIs for package managers. I haven't used one, because I feel like there's no need, but they do exist. I don't know if they support the AUR and pacman though. That probably exists, but you'll have to look it up.