Since you are applying the principle in exactly the same manner (i.e. both you and the gun-grabbers wish to constrain people's property rights on the grounds that it will allegedly prevent various indirect effects that supposedly get people killed), that's a pretty damning admission.
Let's say that we realize your libertarian utopia where everyone agrees not to "initiate force against others," in the sense that you mean.
What then?
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Is that all there is?
Do we then all revel in drugs, pornography and prostitution and pat ourselves on the back for a job well done?