I think the point is that what we think of as an archetypal "general-purpose processor" is a somewhat arbitrary point in the space of possible architectures, an

I think the point is that what we think of as an archetypal "general-purpose processor" is a somewhat arbitrary point in the space of possible architectures, and to think of other designs as in some sense secondary simply for failure to match this particular model is to lose sight of the true scope of general computation. Is it uncontroversial? Perhaps no one would disagree after hearing it spelt out, but I think it certainly is the case that people often naively think of "general-purpose processor" in just the way the author worries about, and that reading something like this can bring about a helpful shift in perspective.