Your points are well made, but there are some other things to consider...
My kites came with an instruction manual which tells me how to do everything you refer to...

And I actually read it to familiarise myself with my new kite ! Am I alone ?
I would have thought that anyone with a grain of intelligence and any care for self-preservation might read at least part of that ?
However, you can't account for those people who blindly buy things and try and use them. After all, they could actually buy this stuff on the internet... That's impossible to police. I have seen it in lots of places.
I would actually be more worried about the teaching if these people aren't questioning how it all goes together or how the safety features work... Yes it is exciting to have new toys, and that enthusiasm to try it out can cause some 'bindness' to these things, but they should have some idea how dangerous this sport can be and be seeking to minimise the risk to themselves. That all being said, I am happy if these people at least stop at some point in the whole process and seek help... And we should give it...
Just to throw something else in as an example from real life, no one gave me any demonstration when I brought my new iron !!! And that could seriously burn me ! I read the instruction manual. I realise that I have invited heaps of scorn now, but it was just for illustrative purposes... And no, I am not a girl !!!

Anyway, just a few thoughts in response...

BAP