"Free time" for a medieval peasant is a very misleading statistic, because it's only counting the amount of time that the peasants worked for their feudal lord - which was about as high as it could be, because of the amount of work that the peasants would have to do beyond that. Without modern technology, they had to gather firewood (I did this on the weekend and it's hard enough with chainsaws, a 4WD ute, a hydraulic log splitter - would take forever with an axe and mule cart), tend their own crops and livestock, mend and hand-wash their own clothes, work on their houses etc, which is all counted as time off work even though the peasant would die if they didn't do it.
The first couple of google results just seem to say your view is a very common mistake/misunderstanding people make when confusion "not working" with leisure time.