Current regulations allow employers to require working more than 40 hours a week as long as the employee is paid overtime (except in the cases of exempt employees). This practice allows employers to terminate employees for not working more than 40 hours--often used in bullying the employee--and promotes a reduction in workforce by providing an environment that enables termination of employees through increasing work hours for those that remain.
This is not to discourage the practice of overtime as many employees are grateful for increased income. However, this is to protect the employee from termination for failing to work more than 40 hours. Working more than 40 hours should be the choice of the employee, not the employer.