Apart from the silliness of pretending there won't be future wars, there is an assumption here that space colonists will be even able to communicate with each o

Apart from the silliness of pretending there won't be future wars, there is an assumption here that space colonists will be even able to communicate with each other. The ones who travel fastest can be constantly outside the spacetime cone of the others, and if they re advanced enough even their lightcones. the universe is vast for everyone to live long and prosper, and sometimes kill each other.