Exactly, if you stick to the very basics with git, you can live a happy life never caring about the internals. If you however want to dig into the depths of Git and use all its power, I don’t get why people don’t think there would be an obvious learning curve.

Same exact thing above applies to so many things in software development, from IDEs, to code editors (Vim/Emacs/Sublime/etc), to programming languages, to deploy tools, the list goes on. There’s a reason software development is classified as skilled labor and not a low end job generally. You’re expected to have knowledge of, or be willing to learn a lot, to do your job.