To be honest, after confirming that Old Liu had indeed betrayed them back then, he had always found it hard to comprehend…
At that time, it was Old Liu who wanted to rally them to rebel against those nobles. And if the rebellion succeeded, given Old Liu's prestige at the time, it was highly likely that he would have become the Central Federation's newest representative. Coupled with his unique identity as a sentient artificial being, leading humanity down an alternative path of coexistence was not impossible.
Why choose betrayal as the path forward?
It was indeed Old Liu who ordered the bombing that killed Elder Long and his group, establishing an irreconcilable vendetta with those nobles. But even after defecting later, what real position or advantage could he have gained?
If not for leveraging the Buddha Kingdom's unique Dream Space, it would have been impossible to found a guild capable of countering the nobles' power.