It seems to be because that Android device users can’t force prompting to set a passcode or PIN, only iOS device can do this action.
https://learn.microsoft.com/en-us/mem/intune/protect/compliance-policy-create-ios
If you would like user to setup PIN, you can consider creating a compliance policy, which requires for setting the device PIN, you can use Conditional Access to block the access if the device is non-compliant.