As a society, we've decided that it's the company's responsibility to provide a reasonably safe workplace. This is a lesson that was learned from the blood of thousands who died or were injured before safety standards were created and enforced. This is why in the US, we have OSHA. Standards for what comprises a "safe workplace" will, of course, vary depending on the workplace. An office processing paperwork has different standards than a metal stamping plant.
By making it the employer's reponsibility to follow OSHA standards under force of law, the employer has "skin in the game." They can be sued, or shut down if they don't comply, or face criminal penalties for, e.g., removing machine guarding.
If they have no responsibility, then they have no reason to make things safe: just need to pay enough that there's a steady stream of people to replace the ones who die/are injured. People in bad circumstances will take on risk regardless: the babies have to eat.