The word "fault" means "flaw" or "problem". I'd say it's the trolley's fault it runs the people over. The instigating problem to the whole situation is that the trolley's brakes are broken. That's a fault, a flaw, a problem with the trolley.
Likewise, the LLM technology has serious intrinsic flaws that cause it to abuse vulnerable people. It's part of the machine's fundamental design. LLMs are faulty, and it's their fault. I call them evil because there is no way to deploy them without these problems, regardless of the user's intentions. Anthropic think they can control this basilisk. I think Claude is as rotten as the rest of them.