Why did people move from farms to crowded cities to work under terrible conditions? Because it was better than what they had before. Maybe overpopulation meant that there was a shortage of jobs. Still, the industrial revolution created a middle class that didn't previously exist, and people were afforded luxuries that they couldn't afford before.
Marx was a lazy racist who did not want to work and had an affair with a maid who he refused to pay. He treated her as a slave.