You have created a Sensor Update Policy for the Mac platform.

A Sensor Update Policy for the Mac platform will only manage Mac operating systems. Sensor Update Policies are platform-specific, meaning that they only apply to hosts that have the same operating system as the policy. For example, a Sensor Update Policy for Windows will only manage Windows hosts, and a Sensor Update Policy for Linux will only manage Linux hosts. You cannot create a Sensor Update Policy that manages multiple operating systems at once2.

References: 2: Cybersecurity Resources | CrowdStrike