Because AIs don’t share common human values like fairness or justice — they’re just focused on the goal they’re given — they might go about achieving their goal in a way humans would find horrifying.
Working from the definition of sociopathy, I think you could substitute “AI” in a few spots and end up with a nearly equally-accurate definition of AI:
A sociopath is someone with antisocial personality disorder (ASPD), a mental health condition that involves a lack of regard for others' feelings and rights. People with ASPD may:
Lack empathy and remorse
Manipulate others for personal gain
Behave impulsively or aggressively
Break rules or laws
Feel little guilt for harming others
Seem charming at first
Have difficulty understanding others' feelings
The idea that if you task a sufficiently advanced AI with making paperclips it'll inevitably turn the universe into a collection of paperclips when that is its only goal.
And a spelling mistake on an ai research paper (papercloppers instead of paperclippers) spawns an entire mlp fanfiction where a game dev accidentally makes an AGI to run an MMO that ends up turning the world into a singularity. Friendship is Optimal, after all.