I remember an article a while back where archaeologists examined the bones of pre-Columbian women in America. The bones showed the signs of long term debilitating, repetitive work from kneeling and grinding, by hand, corn into flour.
Just last night I watched an American Experience episode on the guy who revolutionized wheat farming. He spent his youth on a farm, harvesting corn by hand, estimating that he'd harvested 1 million ears per season by himself. He was amazed at how wonderful it was to get a machine that mechanized corn harvesting.
I'd much rather mow my lawn with a mower than a pair of scissors.
In the 1960s, my dad was writing a book. My mom would type up the drafts for him. Every new draft meant my mom would spend hours banging it out on the typewriter. Think how much easier that is today with our "dehumanizing" computers. Can you imagine today typing the whole thing over again because you made a misteak?
Machines have largely free'd us from dehumanizing labor, not caused it.