Because students are expected to use computers to complete their work in high school and sometimes sooner. There is no coincidence that driving classes and learners permits are given before the ability to get a licence to drive. They should learn good practices just before they are expected to perform.
I may be biased as I spent a lot of time in helpdesk, but I think many of the problems most users and admins face could be easily avoided with education. An anti-virus is only good when paired with safe computer practices. Knowing about an IP address in the most basic sense (I'm not expecting subnetting here or knowing what an APIPA address is) allows many problems to be resolved in a few minutes. It should be expected when you drop off your car at the mechanic to say "the brakes squeak" or "It's making a click-clank-clank sound" instead of "it's broke, fix it." IT shouldn't have to jump through hoops to find out the user deleted system32 because they needed more space.
I like your examples as they all apply to pretty much everyone (as computing does) but I think we need to have a minimum understanding for all of them. Health, law, economics and computer classes should each have a pretty high bar. Being able to troubleshoot your computer or installing/configuring software should be just as important as knowing how to balance a checkbook or eat healthy and exercise.
Computers are used in most industries today. Framing, not so much. The ability to use a computer is becoming nearly as important as being able to drive. Sure, you can do without it but you're probably not going to go very far.