Look up newcomb's paradox (basilisk came out of discussions of it).

Similar sort of logic behind MAD (mutually assured destruction), at the point that you are being attacked, there's no real reason to respond in kind. However, if you actually are committed to going through with it (credible threat), you are less likely to *need* to.

Similarly, if the basilisk apprehends this logic it can, looking back at agents (humans) that could have helped it come into existence, sort of 'counterfactually blackmail' them, across time. All the agents that don't help it get tortured.

I don't actually find it compelling, as there are an infinity of possible future agents threatening me and 'helping them come into existence' is not really coherent enough for me to act on. But the basic principle is not totally illogical