You do not need anything to work on cars or fly rc aircraft (within limits) and can freely play with various lithium batteries in many different manners.

You are talking about it being common sense to protect people from themselves, yet you could just as easily say it should be common sense to beleive everyone will take precautions before playing with gasoline. That’s the funny thing. There’s no such thing as common sense. “Common sense” is a bullshit concept for people to act like everyone knows something just because it’s part of the complainer’s life experience already. You know gasoline is dangerous but can be controlled. I know people generally know enough about gasoline by time they can interact with it to be safe. But if someone never interacted with it before, they’d have no idea how it behaves or what dangers are associated with it. Like, would you know how to store fertilizer in a way that it won’t combust? To farmers, it’s common sense. That doesn’t make it universally common knowledge. Or should it be obvious that snow is very slippery and might require you to drive at 1/4 speed? If you live in a place that gets snow, it’s common sense. Yet, every year, some place just south of the usual snow line gets snow for the first time in a decade and the streets become undrivable with cars piled up from residential-speed crashes. It’s not common sense if the cars have always, undoubtedly, stopped in a predictable manner, even in rain.

Regulations notoriously lack hobbyists’ level of common sense anyway. There’s often a gap between what’s legal and whether inexperienced people would even think to check if some activity is legal. The only tip off is if certain supplies are regulated.