> all future cooperative parties are at an automatic advantage over aggressive parties.
No, that does not follow, because it assumes any cooperation gives sufficient leverage to be able to resist. But an enemy lobbing kinetic kill devices at high speed from locations that does not give them away would require far more advanced tech to stop.
> What do you think the long-term prospects are of a species that goes around flinging RKVs at people? No more North America and no more Eurasia, if that happened. Maybe South America and Africa can pick up the pieces. Just because irrational hyperaggressive actors can briefly exist doesn't mean you're likely to encounter them. They won't survive for long.
On Earth. In space, throwing kinetic kill devices at people won't affect your own territory, and can at least in theory be done without any possibility of tracing it back to you - you "just" need to accelerate a bunch of them outward to starting positions far from your home system. Any civilization smart enough to be able to build devices like that would be smart enough to build autonomous ones that would become operatonal first when in a position that wouldn't give them away.
> MAD exists whether or not any particular participant believes in it, because it's just the cause and effect of competing powers each with their own agency. Or else we wouldn't be here. Even the Soviets knew that a possible US first strike was better than a guaranteed US retaliatory strike, which would happen if they struck first.
The point of the lessons Able Archer is that there were strong indications the Soviets thought there was a line at which point a first strike to preempt a US first strike would be preferable, and that they thought they were getting close to that line.
> The whole "Fermi Paradox" arguments are based on an extreme form of "eventually, we should expect to see aliens, so why haven't we already?" This doesn't mean aggressive civilizations don't exist, but the reasons to think they're prevalent are overblown.
I've seen nobody suggest we have strong reasons to think they are prevalent. That is missing the point. It's one of many possibilities, but one where the temporary existence of even one in any given "neighbourhood" close enough to strike before we've gotten advanced enough to defend against compact kinetic kill devices hammering us at a decent percentage of c (or worse options we don't know about) would mean we'd already be doomed without knowing about it.
It doesn't even need to be a long-lived one. There just need to have been one alive when our first radio signals hit them.
It doesn't even need to successfully kill most civilization. For it to resolve the Fermi Paradox, attacks just need to happen often enough that those who survive quickly decides hiding is the best option just in case.