Because the worker, having far less power than the company, is not in a position to give consent to work dangerously for the pay. We, as a society, instead of

Because the worker, having far less power than the company, is not in a position to give consent to work dangerously for the pay. We, as a society, instead of just banning the ability for the work to be done, instead create a regulation which balances the situation to one which we feel consent can reasonably be given for the work done, as long as the company offers certain concessions.