Your first sentence is correct. You do not understand. And he was quite clear about the issue, too.
Quest logs record past events too, which is vital for RETURNING players. Corruption scores and vague instructions to trigger the next event do nothing to help you get back into a story you haven't played in half a year. To remember what happened and which paths you followed how far, you need a proper quest log.
When you do not understand, the solution is not to explain harder, but to start listening.