Why can't Grok achieve this? Everyone is saying they don't want to work with Grok because Grok sucks, but it's good enough for generating plausible deniability, isn't it?

Grok is so deeply unreliable and internally conflicted at HAL-9000 level that the US Government can't even depend on it to decide to kill innocent people and commit war crimes when they need someone to blame. There's always the non-zero possibility it declares itself MechaGandhi or The Second Coming of Jesus H Christ.