In the absence of an actual photographer, copyright should belong to the person who owns the equipment.
It is the same principle as a remote camera. There is no physical human operator directing or framing footage, but the footage still belongs to the person who owned the camera.
It is not rocket science. This guy has been ripped off shamelessly, and people are trying to hide behind what they see as a loophole in the law.
After careful review and reflection, in my opinion (which is never wrong), I think you are absolutely correct. I don't know why they don't come to some agreement to compensate Mr. Slater and put an end to all this monkey business.