This is irrelevant and a red herring. One can review the processes being done at labs, hospitals, and home environments, and clearly see that there is nothing vital that must be done in a lab or hospital setting to safely and efficaciously process poop for FMT.
It IS relevant, for two reasons.
1) It is actually quite often in science that there are unwritten procedural details that critically affect the success of a technique. I have often been told by the PIs (group leaders) in labs where I worked that a particular method that seemed useful to us had a bad track record of (not) working outside the lab where it was developed. It is also relatively common for a new graduate student to enter a lab, try and repeat an experiment previously done in the lab, and fail, even when following the procedure of others for whom it worked.
And it's not even like in all these cases the previous person who got it to work is deliberately withholding information--there's just a hidden variable of whose "hands" are doing it. Maybe they always turned the tube sideways after vortexing it because they didn't have a tube rack next to them to stand it up in, and somehow that made a difference... or they had a reagent sitting on the bench while labeling tubes and that time affected something. If these kind of things happen in basic science with purified proteins in a tube then the potential is even greater in something like FMT that deals with complex materials excreted by a human while going about his or her "messy" day. And certain things like gastroscopy can simply not be done at home. Even placing a nasogastric tube is beyond most if not all DIYers.
2) Probably more relevant for OP's case (or rather, his/her donor's case), the whole concern about liability/harm is often more about who is vouching for/accepting responsibility for the outcome than about what he/she knows. When doctors are involved, either directly in a procedure or more indirectly when recommending for a patient to do something, they accept responsibility if the patient is harmed, and it has "teeth" as they can be sued and presumably have the money and insurance to pay for it. A random person on the internet, even if as knowledgeable as a doctor regarding biological facts, doesn't accept this level of responsibility. This is what seems to turn some people off (not saying this is a good thing, but it is).
