> …it is pretty sad since this is not a matter of taste or political inclination: there must be a single truth

This is more of a salient point that you perhaps realized. In life there is no single absolute, unknowable truth. Philosophy has spent the entire span of human existence grappling with this topic. The real risk with AI is not that we build some humanity-destroying AGI, but that we build a machine that is 'convincing enough' — and the idea that such a machine would be built by people who believe in objective truth is the most worrying part.