The Samsari diplomats warn humanity that strong AI had always previously ended in disaster, and that despite the best efforts of anyone in the galaxy solving the Control Problem appears to not be possible. Such attempts were responsible for previous near- and complete-extinction events. Effectively, Strong AI is banned by the Intergalactic Community (IGC), but limited forms of AI are allowed. as a probationary member of the IGC is allowed to make mistakes that would extinguish its own species, but not those of others.
But humanity was especially factional compared to other species when it had ascended to the stars, leading to a decentralized and uncontrolled development of AI. Most other races had managed to establish top-down control over this sort of development, so few had made the misstep of letting AI get out of control.
At some point, the various factions in what would later become the ULISIS (probably UN at this point) gave into powerful competitive incentives to develop strong AI in secret. This led to its development outstripping people's ability to control its volition. Reckless integration of IOT meant that nearly everything was vulnerable to AI control. Nearly an extinction event, and led to many independent bodies either being fully exterminated or agglomerated into larger entities that were able to end the threat.
Study of the Samsari's crystal components led to advances in crystalline data structures that allowed true AI to be feasible.
This led to the AI Wars and the near extinction of several species.
Intergenerational trauma from this threat has led to a widespread distrust of automation.