I don't mind doing a little light reading before heading into a dungeon. Most of the time I can even justify it from my character's perspective because what adventurer in their right mind would wander into a dungeon without first finding as much information as they can about it. I just don't want to inadvertently spoil a story element for myself. That said, I don't expect people to have read up but I do expect them to say that they're new when I ask and listen when I do go over strategies. There's no excuse for essentially being a troll.