Why do we need a “positive duty” to prevent harm?

In 2023, a Royal Commission into Violence, Abuse, Neglect and Exploitation of People with Disability recommended that the Commonwealth Disability Discrimination Act 1992 be amended to introduce a positive duty on all duty-holders to eliminate disability discrimination, harassment and victimisation. This echoes the imposition in 2022 of a positive duty to prevent sexual harassment. Occupational health and safety (OHS) legislation has had its positive duty to prevent work-related harm since 1985. So why this current push for positive duties?