"Moderation is guesswork" means that we can't always know what someone's post means, nor their intent, nor for sure what effects it will have. We can only make guesses (i.e. interpretations), and those are inevitably wrong sometimes.

We can't not make mistakes. The best we can do is acknowledge when we make a mistake and do what we can to fix it.

> I censor whatever I like (dislike), I guess

If you knew how many comments I dislike on HN, you would no longer have that perception.