But in reality, so often to make an "informed decision" requires far more knowledge than is practical to have. We can't be detailed specialists in everything. Say I take my car in for repair because it is running rough. If the mechanic blamed the power steering. I might question it, but perhaps a leak in the steering pump might possibly drain off power to cause a problem. The point is that rough running could be from any number of problems. Without knowledge, experience, and diagnostic tools, it's hard to know what's what.
When I bought my last car, I also bought the professional shop manual for the very reason you describe. It was worthless to me. I didn't have the tools they called for, I didn't have the ability to do the tests or adjustments they called for. (How does one unscrew a stuck screw? I don't know.) I had several problems that weren't identified in the book.
With computers and the Internet, even experienced users have a trouble because things have become so complex. Say I'm on the 'net and it stalls. Screen is frozen. Is it my PC? If so, what in my PC? Is it in the connection? If so, where in the connection (my phone line, the phone company, the ISP, the sending site?) When this happens to me I have some idea but usually I just wait and hope it fixes itself; at worst, I reboot.
Someone whose job or hobby it is to set up Internet connections or PCs probably would have some idea of the problem and know what tools to use. Many correspondants in this newsgroup fit that category.
Keep in mind that today the computer world is quite specialized and has been for many years. We have specialists on mainframes and micros. We have specialists on client applications and systems programming (ie compilers, and software installation and maintenance). Networking. Databases. Hardware.
To put it another way, presumably a pediatrician could treat an 80 year man with heart disease, but it might not be the most effective treatment.
I began using PCs with DOS and the Internet with command style prompts. I feel this background was very helpful to me in understanding stuff (along with training and programming experience). But the reality was that far too many lay people found DOS commands too intimidating, getting the spelling of the command and its operands exactly right and knowing which commands and operands to use. A lay person would probably confuse the difference between MOVE [transfer something to another place leaving nothing behind] and COPY [make a duplicate of something in another place].
Lay people wanted to jump on the computer right away and download fun stuff. They didn't want to know from backward slashes and normal slashes; from dashes vs. underscores.
How "democratic" do we want computer usage to be? Ham radio operators have to be licensed, they have to study and take a test before being allowed on the air. Should computer users be required likewise? Website hosts? I don't know the answer.
The sad part -- which validates your argument -- is that computer crime exploits the weaknesses you are concerned about. The super automation, instant executing macros and commands from a simple click, has made it easy to sabotage and evesdrop.
I'm amazed that youth -- who would instantly run away if a stranger approached them and asked personal questions -- freely distribute very personal information while on-line.