Suggestion. If it bothers you that much, type the following simple text command into your chat, and retype it when you leave the exploration area......

/hud dlist

Problem solved. You can't see the objectives, so for all intents and purposes they don't exist to guide you. Explore, kill things, whatever. You might get a bonus if you complete some of these "hidden objectives", but you won't know what they are unless you deliberately try to look to them for guidance. Fully, unguided exploration, as you desire.....