This is not true.
First, the timespan and vast differences of local laws makes this generalisation pointless.
Second, for anyone who was a serf or landless or didn't had enough land to feed himself and his family it's right out of the bat, they worked dawn till dusk nearly entire year, there was always something more to do. People today working multiple jobs just to survive and still being crushed by debt can relate.
Third, even if we look at this meme in the most generous way possible, that is portraying free wealthy peasants (which were usually a minority), 150 days a year are only typical field work. Outside of that they still need to do after field works (for example threshing and cleaning grain was taking months each year), tend to animals, produce nearly every tool, item and cloth they use in house and field, and so on and on and on. And while some of the big holidays like Easter were free of work, 90% of those "church holidays" didn't mean "free of work", most of them meant literally nothing but a way for illiterate peasants to mark the passage of time, for example they didn't say "15 november", they said "4 days after St Martin" (it worked precisely because there were so many holidays in calendar).
So no, unless you're really fucked to work 14+ hour workdays for 6/7 days per week with just a few red days in calendar and no paid vacation you do not have less holidays than a medieval peasant.
And last disclaimer, this don't even mean that capitalism good, though it did bring an improvement in many times and places, but it's that we shouldn't try to romanticise other bad times.
We should move forward to socialism.