It sounds as though you are wrestling with the question of when legal prior restraint is appropriate. Prior restraint prevents one activity or event in order to prevent a secondary, related activity or event. A law against murder is not prior restraint, but a law against carrying a knife/firearm/lead pipe in order to prevent murder is prior restraint.
A law that makes it illegal to do something reckless is not prior
restraint. A law that makes it illegal for a responsible adult to do
something that is not reckless in itself, such as carrying a firearm, is
prior restraint. There is a difference between DUI and carrying a firearm. DUI is the reckless endangerment of others. Therefore, a law that makes DUI illegal is warranted and not prior restraint, but a law making it illegal to carry a firearm is not warranted and is prior restraint. The law prohibiting the pointing of a firearm at someone without just provocation (reckless endangerment) is warranted and not prior restraint. Those who advocate prior restraint want the law to make it illegal to carry a firearm (the initial activity) in order to prevent someone from pointing a gun at another (the secondary, related activity). Another prior restraint law, Prohibition, made the production, sale, and consumption of alcohol (initial activities) illegal in order to prevent drunkenness, DUI, dissolution, and broken homes (secondary, related activities).
A man who is not motivated by the safety of his 4-year-old son (a high motivation) to keep his firearms out of his son's reach will not be motivated by a law that makes leaving his gun unattended illegal (a low motivation). What's more, locking up the gun may have the unintended consequence of rendering the gun inaccessible in the event of a home invasion and may result in the deaths of everyone in the entire family. So a law seeking to impose this type of prior restraint (a law requiring that guns not in use must be locked up) is neither practical nor desirable.
Children must be taught about the dangers in their environment. They don't know that hot stoves burn. They don't know that crossing the street without looking both ways is suicidal. They don't understand that gunshot wounds kill (and, worse, TV teaches them that good guys usually survive gunshot wounds). On top of all that, they don't comprehend the consequences of dying. (And many adults don't either.)
Teaching children about danger takes a while, but teaching them responsibility takes even longer. Some handle it fairly well, some don't, but every young adult does some irresponsible things. So laws of prior restraint (regarding drinking, driving, gun possession, making legally binding decisions, etc.) are in force to limit children's access to these activities until their parents and/or maturity can impart to them some level of intelligent responsibility.