*: except Leto II, and he doesn't say much about it
(This may have been to postpone or prevent the breaking of the Spice/Guild monopoly on interstellar travel by the Ixians.)
After the Scattering and the fulfillment of his eugenics program with the Siona gene, he no longer cares, because it is no longer possible for even AI to eradicate humanity.
In fact he also explicitly prepared a renewal of computing and thinking machines in order to break free from spacing guild
This is an important distinction. It's also the case that Leto needed the Ixians for the no-ship technology, which he also regarded as of extreme importance for the same reason. Which also, remember, the Idaho gholas had to be confined to no-ships so they, lacking the Siona gene, wouldn't be visible to prescience.