Why can't I manage role access for some objects?

For secured objects where data security isn't yet available for spreadsheet data loading you can't manage role access in the spreadsheet template. You can manage role access only for unsecured objects and objects where data security is implemented for spreadsheet bulk loading.

Check the read-only Assign Roles to Template field on the Define page of the template. If it's set to Disabled, then you can't manage role access for the object.