Why are nukes a thing of the past?

[Johnny1A.2]

Originally Posted by Keiko

It could copy itself. If for no other reason than to have someone to play "Kill all Humans!" with.

This isn't a stretch, when you think about it. Consider that the real world has the Voluntary Extinction Movement, and similar fringe outfits. With THS tech and assuming a single member of such a group with access to substantial money, you could well enough magine the more fanatical members of such a group 'ghosting' themselves. The only reason such ghosts would not then xox themselves to multiply their numbers is...well, there is no reason other than law/custom. Once you assume a group with such motivations, it's not probable that they would balk at that.

Xoxing is like nukes, in that respect, the absence of it is necessary at a meta level, because it changes the whole setting into something else.