If everyone could be trusted with nukes, sure. But the problem is, plenty of rogue nations and terrorist groups will use nukes as soon as they can get their hands on them. That is why the global community (pretends to) try hard to keep countries like Iran from getting them.

The thing is, a responsible gun owner can be trusted with assault rifles because they're responsible. Responsible people aren't the problem here, so it makes no sense to me to pass gun control laws that affect them and not criminals and the irresponsible.