The ones after 1970 were like "hey, watch salt dissolve in water."
With high explosives, governments tend to go so far as to require a licence for handling. Fine for breaking that is enough of a deterrent. It's relatively easy to acquire, because otherwise that makes explosive use rather tricky to monitor.
Sales and widespread manufacturing is regulated separately.
Easier and cheaper to get than CFC gas license. Or the general chemical laboratory license required to do such experiments like synthesis. (You can go to a lab and practice there, with supervision. Much less silly, more expensive.)
They're of course limited by volume, just so you don't go building unlicensed rockets and mines.
To give an example with current technology, drones are being regulated now and likely will get remote off switches one day that police can trigger, but for that regulation to be effective, self built drones have to be under a similar regime... so maybe in the future it will become illegal to own innocous drone parts without a permit, etc.
Do we want to distribute science kits that allow people to play around with viruses? Sure, most viruses are affecting bacteria and playing around with them is fun, but if you can also change their genomes with those kits, some idiots might use them to make a superbug.
Your rights end where mine start.
Let’s be real here: a mathematical majority is unable to afford flying anyway. This freedom people ramble on is really economic dominance of the majority for minority benefit.
Stop living in an emotional clean room. The literal world doesn’t have to give a shit about your bubble.