Consider someone for whom there are one or two specific subjects that will cause them a great deal of distress. These are particular to the individual--even if something in the wild reminds them of it, it's so indirect and clearly not targeted, so it would be rare that anyone would actually find it without getting into the individual's confidence.

Now, put that individual alone with a transhuman intelligence trying to gain write access to the world at all costs.

I'm not convinced this sort of attack was involved in the AI box experiments, but it's both the sort of thing that could have a strong emotional impact, and the sort of thing that would leave both parties willing to keep the logs private.