If the military today wouldn't even have to get off base to fuck up the opposing side (proven false in recent conflicts btw) why does it matter if they're on their turf? Your own reasoning doesn't make any sense and ignores a ton of conflicts. You mentioned Afghanistan, who's in charge there now, is it the US?
The statement wasn't about how many people on whichever side die, but that pretending that "You don't need a gun to defend yourself because the federal government has missles" is an extremely poor, provably false argument. I support stronger gun laws, it's just a really bad take.