I do not agree that the picture there really describes a hard work. Yes, the author itself might suffer greatly when forced to do it but it does not necessary a

I do not agree that the picture there really describes a hard work. Yes, the author itself might suffer greatly when forced to do it but it does not necessary apply to the ladies photographed. The sky looks to be overcast, so it is not particularly hot, air is supposedly fresh, the work is not mentally challenging, so you can think your thoughts, sing or socialize. Unless they push themselves too hard. Work is hard when you push or you are forced to push yourself due to external forces - environment, used heavy equipment, management expectations etc.