You seem to assume that any physical process must be reversible, absent supernatural forces driving it in one direction. I fail to see any good reason why anyone should believe such a thing.
My knowledge of biology and chemistry is little more than a patchy recollection of classes that I took in high school more than 30 years ago, but I seem to recollect that there are all sorts of physical, chemical, and biological processes that go in one direction only, usually for reasons having to do with entropy and the transfer of energy from a determinate structure to a free form. A plant cell converts light and carbon dioxide to sugars and other organic compounds. Why should you suppose that the process should be reversible? The idea reminds me of the academicians in Gulliver's Travels who are trying to release sunlight from cucumbers.
Hmm, you do raise a reasonable point regarding the law of entropy... but if I recall correctly, certain critical processes are perfectly reversible, like osmosis. If you placed a cell in a concentrated saline solution, for instance, it would get dehydrated - putting it into distilled water would rehydrate it.
Granted, we are discussing mechanisms beyond mere hydration problems, here. I'll admit that the premise is most probably inaccurate, but I just find the idea of meat-bags being animate to be... a tad beyond what conventional science has to offer.
Just a personal opinion, and let me state for the record that yes, I do see the logic in your arguments