Guns are no more designed “to kill” than knives are. Guns are a tool, designed to fire a projectile. Knives are a tool, designed mainly to cut.
While it is slightly irrational to just say “yes, private citizens should be able to own tanks, anti-aircraft weapons, etc,” the general principle of it is true. Every time someone attacks the 2nd Amendment and brings into it the “sporting” use of a gun, they have immediately conceded that they either didn’t pay attention to history, or they just disregarded it. It’s sole purpose is to allow the citizens to defend against tyranny.
While the average citizen would never be able to afford such an arsenal, lucky for us more and more people are waking up and hopefully we wouldn’t need private citizens with this stuff. Hopefully enough military/law enforcement personnel understand what is going on and side with the people rather than the government.