Game theorists can't work out that cooperation is always rational because it also implies that the stupid differ from the smart; that reality is counter-revolutionary and privileges the competent over the incompetent.
One of the simplifying assumptions in the finite iterated prisoner's dilemma is that both players are perfectly rational. They can reliably figure out the optimal strategy and not only that, but can see the other side is also rational and realize they can also figure out the optimal strategy. That is, they have IQs north of 145 or 160.
In other words if we overstrain this assumption, if we assume instead the players aren't all that smart, we conclude they will use suboptimal strategies. Either because they make a mistake or because they run out of mental RAM before they work out what the other guy is thinking.
If we assume cooperation is the suboptimal strategy, then we're being nice to stupid people.
If we assume defection is the suboptimal strategy, then we're being mean to stupid people, and that's counter-revolutionary.
Game theorists tend to have distant inferential horizons, and can indeed at least feel these consequences, even if they don't acknowledge them consciously. Being a proper revolutionary is more important than not promoting treachery and isolation, of course.