there is nothing "basic" about this. something that seems pretty obvious to you may not be natural to someone else.
i think the single-click navigation or opening of files was done to mimic how hyperlinks on the internet work. some people are wired that way.
on the other hand, some people have a completely different brain configuration: they think that a single-click should select whereas a double-click should open a file.
there are people who do not agree with both these options. maybe, they want everything to work via audio commands.
how do we decide what the default behavior should be?
the answer is: leave it to the user.
So I don't think my mother has ever grokked the difference between single- and double-click.
I watched her double-click web links all day long while sitting at the desktop Windows Vista computer. I couldn't do anything to educate her on when to use single and when to use double, because that distinction is just lost on some people, you know?
So I would often send her YouTube links in email, and she always reported back "I couldn't watch this; the sound was horrible! Unlistenable!"
And years, yes years, later, she reported to me that she'd figured out what was messed up about her YouTube experience, because she had been consistently double-clicking every link in her email, and opening two browser tabs to the same content, and it didn't bother her unless it was autoplay video, which would offset the sound by several milliseconds and totally mess it up.
It's how both major desktop OSes have worked for literally decades. It works very well. Why be different?
Mimicking hyperlinks doesn't make sense because you never want to move hyperlinks around or rename them. There's rarely a reason to select a hyperlink.
i think the single-click navigation or opening of files was done to mimic how hyperlinks on the internet work. some people are wired that way.
on the other hand, some people have a completely different brain configuration: they think that a single-click should select whereas a double-click should open a file.
there are people who do not agree with both these options. maybe, they want everything to work via audio commands.
how do we decide what the default behavior should be? the answer is: leave it to the user.