There's nothing special about Grok in this regard. It wasn't trained to be a MechaHitler, nor to generate CSAM. It's just relatively uncensored[1] compared to the competition, which means it can be easily manipulated to do what the users tell it to, and that is biting Musk in the ass here.
And just to be clear, since apparently people love to jump to conclusions - I'm not excusing what is happening. I'm just pointing out the fact that the only special thing about Grok is that it's both relatively uncensored and easily available to a mainstream audience.
[1] -- see the Uncensored General Intelligence leaderboard where Grok is currently #1: https://huggingface.co/spaces/DontPlanToEnd/UGI-Leaderboard