Are you saying they use GitHub (via the web editor?) but have never heard of Git? or don't know how Git works? or just don't know the Git CLI? or something else?
I have seen the same phenomenon where I work. However, I disagree with the implication that this is limited to young people. I know of a few people that are 50 and 60 years old, that have been using source control for 30+ years, that didn't have any idea that git and GitHub were different things. Now, they were easy to set right; the concepts are all familiar to them.
My experience with younger folks that have never been outside the Windows world has been that it was a lot harder to make them understand. Young folks with a unix-y background were much easier.
I think many a junior just never initialized a repository, and 'git clone' is what they've used to "get a repository". So I would forgive them for thinking that a remote is needed for having a repository on their drive.
IMO the issue here is just that people think of git as it was something like SVN where you need to have some kind of external server to host project. Which isn't surprising as most of the time (when you cooperate with others) you do exactly that: push changes to one server. Idea of decentralization and independent copies of repositories may not be easy to grasp for newbe, because it's really technical concept.
How many people know that you can just run `git daemon`[1] to share your local repo (very insecurely, mind you) to anyone that can reach your machine? No central server needed.
IMO the "issue" that the concept of a free remote storage/backup makes sense, while doing random things on your own computer doesn't have much value for a lot of people.
".. you don't have to keep the previous versions, so it saves space? OK... No, I was talking about the real git."
