Something to consider about "Dark Forest" scenarios is that there's no particular reason to think that a given species would be more benevolent towards its own

Something to consider about "Dark Forest" scenarios is that there's no particular reason to think that a given species would be more benevolent towards its own kind than some other alien species. If you think about how humans behave, I think if we ever get to the point where we're a multi-planetary species, those two planets aren't going to trust each other very much. If we expand to other star systems with years of communication lag, it'll be even worse -- both societies are going to be constantly expecting a hail of nukes to fall out of the sky one of these days, unless there's either a plausible defense against such an attack, or a reasonable expectation of mutually-assured destruction.