Because there is nothing to be learned or gained from it. This isn't a Heath Kit from 1975. Electronics are fully integrated components now. You're paying for an experience. Typically DIY implies a cost-savings.
It's like going to one of those restaurants where you have to cook your own steak at the table and realizing part-way through wtf am I doing?
Do you also get upset when people buy Lego sets, model airplanes, or jigsaw puzzles? It's the same thing.
And FWIW, it's the exactly same reason most people were buying DIY electronics kits in '70s, '80s, and '90s.
> It's like going to one of those restaurants where you have to cook your own steak at the table and realizing part-way through wtf am I doing?
And yet, people keep going to these restaurants.
Perhaps it's just that people find enjoyment in different ways than you.