Disabling inheritance may be necessary when dealing with permissions inherited from parent directories or system-protected accounts, such as "Everyone" or "Domain Users".
These inherited permissions cannot be modified or removed directly using icacls unless inheritance is disabled first.
By disabling inheritance, you gain full control over the permissions, allowing you to modify or remove them as needed.
However, if permissions are not inherited, this step is not required, making the necessity dependent on the object's permission structure.