No. I said EITHER. Everybody is not in the same level in the second case, where an ogre or a dragon is 10x your level and you will never be able to beat it.
Obviously you couldn't simply barge into an ogres cave and attack it (That's assuming an ogre is actually stronger than a coordinated group of human fighters, nobody is saying that these characters will be the equivalent of 1st level)
If you really want that ogre/dragon dead you'd have to plan ahead, decide on the best time and place to fight it, get hold of proper gear for fighting a much larger enemy, perhaps set a trap or recruit mercenaries for backup.
Wouldn't that be more exiting than bashing in rats until you have enough levels that you can attack the ogre head on?