Goddamnit, it's a grey area, it's complicated.
No, it isn't actually. A guy who stabs someone with a knife can go buy a knife the moment he's released from prison. Why isn't that "complicated". What "complicates" the gun thing is the mass of terrified white guys with tiny **** and dwindling economic prospects trying to find some sort of way to feel powerful, and us deciding we should enable that with weapons capable of mass murder instead of **** cars or some other coded status symbol.