But there are a large number of singers/guitarists with absolutely no knowledge of how to read written music or with any understanding of music theory and I have managed to teach several of them basic ways to accompany their songs so they sound 'right'.
Your explanations may be accurate and perfectly understandable to people with music training but I know a lot of people who wouldn't be able to follow it at all.
So if someone with limited music asks about modes, most of them can find a keyboard and try out the white notes (if someone tells them which note is C) and hear for themselves the difference in sounds.
BTW 'Click go the shears' was one of the 'Australian folksongs' enforced on kids at school here in NZ - I really hated it back then and don't think much of it now.
Robyn