Why do you summarily conclude that separate infections at Bushehr did not take place? You have access to intelligence that the rest of us do not?
Well for one a nuclear power reactor doesn’t spin like a centrifuge. You’re talking apples and oranges when you try to compare the two.
The publicly known purpose of the Stuxnet virus was to ruin the centrifuges used to purify the radioactive fuel used in the reactor. My comment was based on that.
It is, of course, possible that Stuxnet has multiple purposes, or that there are multiple viruses in the wild that directly target the reactor.