However, others are not so limited- better computers mean better treatment of disease from better drug design and detection. Similarly, more efficient chips mean less use of oil (since less energy cost for the same computation) and less use of rare earth elements (which while not actually rare, are distributed in ways that make them inefficient to obtain except for in specific locations).

This is true. I'm not claiming that ending Moore's law via regulating or attacking chip fabs would only affect brain uploads & de novo AGI, without affecting any other existential threat. The question here is whether the chip fabs are vulnerable and whether they would affect uploads, which I think I've established fairly well.

It's not clear to me how the latter would go: nanotech and bioterrorism both seem to be encouraged by widespread cheap computing power, and forcing research onto highly supervised grant-paid-for supercomputers would both slow it down and make it harder for a rogue researcher (as compared to running it on his own laptop), but the slowdown in global economic growth has horrific opportunity costs involved.

Hence, whether this is a strategy anyone would ever actually want to use depends on some pretty difficult utilitarian calculuses.

However, there's a fair bit of controversy over how much guns were actually suppressed, and the point has been made that the Edo/Tokugawa period was relatively peaceful. More to the point in this context, almost no scientific or technological research was occurring in Japan of any sort until the Meiji restoration.

Yes, I've read about that. Even the contrarians admit that guns were hardly used and locally manufactured guns were far behind the local state of the art.