In my opinion it's not "installing" apps in Mac that can be "unintuitive", it's grasping the fact that a lot of applications are self contained; setting up an application on your OS is as simple as dragging it to a folder on your hard drive (generally) and it can be unintuitive to users that are accustomed to Microsoft installers and package managers.
OSX by default (at least for DMG's) opens a window with the extracted content and most include "setup" instructions ("drag FOO into the Applications folder"), so it's not hard to miss.
OSX by default (at least for DMG's) opens a window with the extracted content and most include "setup" instructions ("drag FOO into the Applications folder"), so it's not hard to miss.