You should not get error when you do it like this:
PS D:\dev\deployment-stacks\lz-policy-management> Get-AzManagementGroupDeploymentStack -ManagementGroupId Sponsor | Remove-AzManagementGroupDeploymentStack
Remove-AzManagementGroupDeploymentStack: The input object cannot be bound because it did not contain the information required to bind all mandatory parameters: ManagementGroupId
as the first command contains the management group the passed object should just be removed as you have at which MG the stack is.
You should not get error when you do it like this:
as the first command contains the management group the passed object should just be removed as you have at which MG the stack is.