Best to read the link first and my comments later.
I have very little to comment on the topic itself, but I do find it odd that Robin takes such a confrontational stance, beginning from the first sentence "It has come to my attention that some think that by now I should have commented on Carl Shulman’s em paper" and culminating with a harsh analysis not only of Carl's conclusions, but about what (Robin believes) made him want to reach those conclusions, as well as SIAI's mission statement in general. There is negative framing, "obsession with making a god to rule us all (well)", that I wouldn't expect from someone trying to honestly represent the other side. It's not that I don't share some of those concerns, but to psychoanalyse (who you seem to have identified as) your opponent in an obvious effort to discredit, is at the very least unfair. I was generally aware that there was some kind of tension between the former dynamic duo of Hanson - Yudkowsky, but it seems to have become full-blown hostility.
Robin does seem to find the courage to say he's glad others are looking into emulations, but the overall vibe I get is of someone protective of a research field they believe they uniquely 'get', someone who feels others should just get in line or get out of the ring, and it's a vibe not uncommon in academia.
Perfect prediction seems like a rather demanding criterion. I can't predict the behaviour of one of my cells perfectly - but that has more to do with difficulty in establishing initial conditions, a lack of knowledge of the laws of physics and computational intractability than it does with a lack of shared heritable material.
Also: some value drift within a single large organism may be seen as being permissible. The galactic federation may tolerate a few rebels - the point is more that it exhibits large scale unity and is not threatened by the rebels - because they are too few or too weak.
Serious disharmony would have to be something larger - disagreement about which side of the galaxy will launch an intergalactic colonisation mission, for instance.