The robot (at least according to the information released to the public) was ultimately preserved, because one, it hadn't conducted any harmful behaviour, and two, it had been fully controlled by humanity. Even if it might have anti-human sentiments, humanity hoped that by preserving it, they could learn more about AI.
"The biggest difference between sentient intelligence and AI is the ability to learn and evolve and the creativity and ability to absorb soul. These are all properties of a lifeform. It is because of this that a robot civilization with sentient intelligence is the third biggest threat in the cosmos that could cast fear even in a high tier space civilization's heart!"
"Only a robot civilization with a sentient intelligence is considered a real threat? Then what about the Zerg race? What kind of evolution did they have to go through to be considered the cosmos' second biggest threat?" Yao Yuan asked ZERO.
