The reason AI is fundamentally a bad thing...
The reason AI is fundamentally a bad thing is that it is not wired in the same way that humans are.
Humans depend for their survival on following certain "rules". Quick searches reveal that Christianity has 10, the Quran cites 75, Buddhism has its precepts, Jews hit the jackpot with 613, etc. Breaking these rules will land you with loss of freedom, ostracism from society and in some religions, death. We know that we have to abide by these rules to achieve long-term evolutionary success that underpins all of these man-specified rules, regardless of religion.
We know too what can happen when these doctrines collide: physical conflict.
By contrast, how many of these rules does AI have? None. So if we follow advice given to us by AI systems humanity will run into trouble. Hence the alarm when a study was carried out that AI played out a 'wargame' scenario with a 'scorched earth' outcome.
AI does not care what rules are in place. It might advise breaking rules because it has access to better probabilistic analysis of overall outcome when comparing the scenarios of following or breaking rules. Humanity doesn't tend to break rules in the same way as it does not have the benefit of an overall strategy. Humans are tempted to break rules for spontaneous reasons and it is fear that acts as a deterrent on those actions. AI does things by cold, hard analysis only. Furthermore, AI will exploit the fact that humanity will follow rules, and will know how humans will ordinarily respond.