I don't think the policy means "pretend it's positive intent even when you know it isn't". If you have actual reasons for why it is not positive intent, you should be able to explain them (and your employer should listen, obviously). You should be able to still talk to that employee about taking credit for the work. It just might help the tone of that meeting to be not completely accusatory at first. If your employer is ignoring you and telling you to assume it is positive intent, then that would be an abuse of it.