The problem is, there may be more to us than just "add macronutrients." We might need things like micro and nanonutrients. We might need variations in the kinds of proteins. The bacteria in stuff we eat might be the key to keeping us healthy in the long term. But how are we ever to know any of this unless someone studies it?
That, in absolutely NO WAY, should be misconstrued with homeopathy, which is absolutely bullshit about water "remembering" molecules that used to be in it.
(Which is not my support of homeopathy - it's just that using the right term is important for discourse. It's important to distinguish between copyright infringement and theft, and it is important to distinguish between different forms of alternative -- that is, not scientifically proven -- medicine).
There is also the added advantage that you also know whether the test subject is complying with the experimental protocols. The disadvantage is that the person running the experiment on you is an amateur that may not necessarily be aware if the experiment is harmful.
Given that many physicians can't be certain of the results when they prescribe treatments and medications, I figure that if they can roll the dice like that without even having a stake in the outcome, people who take greater risks for greater payouts are not crazy. They are just less risk-averse.
Putting someone else's poop in your colon is not that disturbing when you realize that it already had your poop in it. It wasn't exactly squeaky clean before the procedure.
And believe me, the guy squirting strange feces into himself as a personal experiment has thought about this a lot harder than you. Even the guy doing it for a bar bet has probably invested more doubt.
