I think he means that the instantaneous communications system establishes (or exists in) a non-relativistic Galilean frame of reference that includes the sending and receiving ends, notwithstanding that the sender and receiver are in motion with respect to each other, and are otherwise in different frames of reference.
To my understanding, it is generally held that quantum entanglement between all degrees of freedom is invariant across different Lorentz frames. Therefore, assuming that one could apply this entanglement to quantum information processing, it could be said to establish a non-relativistic Galilean frame of reference that includes both the sending and receiving ends.
Stated differently, the entangled particles always see one another as if they are on the same inertial frame, even when they are seen to be in different frames of reference by the communicators. This would have the same mathematical properties as a wormhole in the sense that the 'clock' of the entangled quanta is always synchronized; it is not subject to special relativity.
Anyhow, thanks for understanding the point I've been conveying. Assuming that this is incorrect and quantum entanglement is subject to special relativity in that way, then my hypothetical ansible falls apart. We could still discuss the topic at hand (causality, etc) but we would have to focus on wormholes per se and cut quantum entanglement out of the picture.
It's possible my analogy was ill-considered and incorrect, but I'm not yet certain that's the case. Anyhow, you are prejudiced against wormholes and it seems that you're not the only one! I agree comfort zones are a wonderful thing. =)
As an aside, since you actually seem interested and fairly comfortable with speculative physics, you may find this Everett FAQ quite fascinating. If not, that's OK too!