It's an attractive analogy that a posthuman will be to a human as a human is to an insect. This suggests that any attempt to analyze or understand the behavior of post-singularity intelligence is as hopeless as it would be for an insect to understand human society. Since insects clearly have essentially no understanding of humans, it would follow by analogy that we can have no understanding of posthumans.
On reflection, though, it seems that it may be an oversimplification to say that insects have no understanding of humans. The issue is complicated by the fact that insects probably have no "understanding" at all, as we use the term. They may not even be conscious, and may be better thought of as nature's robots, of a similar level of complexity as our own industrial machines. Since insects do not have understanding, the analogy to humans does not work very well. If we want to say that our facility for understanding will not carry over into the posthuman era, we need to be able to say that insect's facility for <something> would not work when applied to humans.
What we need to do is to translate the notion of "understanding" into something that insects can do. That makes the analogy more precise and improves the quality of the conclusions it suggests.
It seems to me that while insects do not have "understanding" as we do, they do nevertheless have a relatively detailed model of the world which they interact with. Even if they are robots, programmed by evolution and driven by unthinking instinct, still their programming embodies a model of the world. A butterfly makes its way to flowers, avoides predators, knows when it is hungry or needs to rest. These decisions may be made unconsciously like a robot, but they do represent a true model of itself and of the world.
What we should ask, then, is whether insect's model of the world can be successfully used to predict the behavior of humans, in the terms captured by the model itself. Humans are part of the world that insects must deal with. Are they able to successfully model human behavior at the level they are able to model other aspects of the world, so that they can thrive alongside humanity?
Obviously insects do not predict many aspects of human behavior. Still,
in terms of the level of detail that they attempt to capture, I'd say
they are reasonably effective. Butterflies avoid large animals, including
humans. Some percentage of human-butterfly interactions would involve
attempts by the humans to capture the butterflies, and so the butterflies'
avoidance instinct represents a success of their model. Similarly for
many other insects for whom the extent of their model of humans is as
"possible threat, to be avoided".
Other insects have historically thrived in close association with humans, such as lice, fleas, ants, roaches, etc. Again, without attempting to predict the full richness of human behavior, their models are successful in expressing those aspects which they care about, so that they have been able to survive, often to the detriment of the human race.
If we look at the analogy in this way, it suggests that we may expect to be able to understand some aspects of posthuman behavior, without coming anywhere close to truly understanding and appreciating the full power of their thoughts. Their mental life may be far beyond anything we can imagine, but we could still expect to draw some simple conclusions about how they will behave, things which are at the level which we can understand. Perhaps Robin's reasoning based on fundamental principles of selection and evolution would fall into this category.
We may be as ants to the post singularity intelligences, but even so, we may be able to successfully predict some aspects of their behavior, just as ants are able to do with humans.