Why? The reason is simple — there can be multiple contributing factors:
- Microbiome Bacteria
- Fungi (i.e. Dysbiotic microbiota in autistic children and their mothers: persistence of fungal and bacterial wall-deficient L-form variants in blood 
- Virii (i.e. Viral exposure and autism., Autism in a child with congenital cytomegalovirus infection.)
The second factor is the ability to upload to MicrobiomePrescription which gives access to machine learning and artificial intelligence of the microbiome as a whole.
One of the key factors that I seen on many microbiome providers is “the best of intentions, and the worst of executions”. Actually, not the worst of execution — rather simplistic analysis, typically created from product manager concepts and executed by software developers. There is no heavy-duty statistical/ machine learning/ artificial intelligence resource involved. The why’s is simple… those types are in very high demand by Amazon, Facebook etc with starting salaries exceeding the CEO salary of microbiome provider. Bottom line, take their conclusions with a big grain of salt – often their “gold” with be pyrite or iron sulfide (FeS2) AKA Fool’s Gold.