Not everyone must be a plumber or electrician, but we're well-served by having some basic knowledge, and an ability to find answers to the questions that arise as we do basic handywork, such as changing a lightswitch or replacing a faucet. Similarly, we are well-served as a society when we can answer basic questions about our democracy past the age of 18; IE, shortly after testing ends, and typically before it actually matters - when voting.
Not everyone needs to become a licensed electrician, or have a deeper-than-average understanding of civics. But knowing someone you can trust with an answer that isn't purely to line their own pocket is still important.