To rephrase: Why should anyone even be allowed to own lethal weapons?
What does it mean to be allowed? People are born with lethal weapons. Bruce Lee simply perfected the usage of his.
It's a rhetorical question that I asked, to rephrase the reason behind the initial question asked by the OP, who asked the original question: "Should true christians own lethal weapons?" Because OP's question was being specific only to asking Christians only.
But it was your explanation instead, wherein you said that a person's built-in capability i.e. Bruce Lee, can use himself as an alternative "lethal weapon," rather than actually using an actual lethal weapon device.
The lethal weapon that is dangerous is the mind. It is driven by a person's spirit. If it is not used as a lethal weapon, it can do marvelous, wonderful things... just as guns can.
Besides, who will limit people from having guns? Other people with
their guns? God could have if he had wanted. So, who?
Just to repeat what I've said earlier: "weapons were created either to be used (as it was intended to be used) against an opponent, or it may have been created to be used as a deterrent instead."
And to explain further what I meant: I am merely mentioning a fact, that weapons are either created to be used as an offensive threat towards an enemy and it may also be created to be used as a defensive deterrence against an enemy as well, that's all.