I think the average medieval farmer understood how to harvest food and draw water, yes. This isn't as esoteric as using SSH in 2026. Knowing where your necessary resources come from should be basic knowledge.
For a more modern context of why: I hope people don't simply rant about "why are groceries expensive" and simply believe that a single politician is the reason and that an upcoming politician will magically lower prices. A medieval farmer would not see their crops having low yields and ponder why there's less food.
>This is like saying the internet is when two computer send 1s and 0s over copper wire.
If they aren't specialized in computers, it'd be a start. Things are abstracted, so I'm expecting less knowledge of bits and assembly and more about landlines and isps.
In short, if you use and pay for something everyday, you should understand who to hold accountable when it breaks, or suddenly gets more expensive. Knowing that one breadcrumb can start the trail for further thinking.