It's not strictly pedantry (or indeed that newish) Bunnahabhain.
The Dark Ages were so-called because their seemed to be a lack of documentation from that era.
We now know that their was rather more than we previously believed.
The term Middle Ages was coined by Renaissance Scholars to indicate the gulf they perceived between the "Enlightened" Classical era, their own "Enlightened" times & the "Barbaric" period in between.
It tells you far more about the inflated self-esteem of Renaissance scholars than it does about a key period of European history.