"A" post-biological intelligence? Why would there only be one?
A post-biological intelligence would want to migrate to another system so it can build its own hosting substrate and increase its own resources without fighting with someone else. (Well... at least initially.)
Explanations based on "oh, they'd never want to do that" need to explain not why "a" post-biological intelligence might conceivably under some particular circumstance not want to spread out, but why all the post-biological intelligences never do. That's a much harder argument to make.
A post-biological intelligence would want to migrate to another system so it can build its own hosting substrate and increase its own resources without fighting with someone else. (Well... at least initially.)
Explanations based on "oh, they'd never want to do that" need to explain not why "a" post-biological intelligence might conceivably under some particular circumstance not want to spread out, but why all the post-biological intelligences never do. That's a much harder argument to make.