I've always found it ridiculous how farmers are considered unskilled. Like just anyone can balance on a moving trailer while throwing hay bailes around. It's just soo easy to take a tractor apart and back together again because a gasket blew. It's so easy to have a biggillion different skills varying from field to field. Literally everyone I know can run a mile while carrying a sailt lick. Farmers are just dumb and untalented. Am I right. /S
Quite often in films and books farmers are often depicted as dumb guy with funny twang accent. Also farmers are also depicted in the picture above. Yea it's trying to say all labor is skilled labor but hey OP felt the need to include farmers in the picture.
In the past there probably was more manual labor that couldn't be automated, so there were many jobs in farming that would be considered unskilled. I would guess that there are many fewer jobs like this now.
...and yet, (almost) everyone has a back and a pair of feet. Hence, unskilled. Doesn't matter much if it's Elon Musk, my next door neighbor or some teen from Thailand picking strawberries. The value of their input labour will be the same in this context.