I would still be cautious with such findings. Many autistic people are picky eaters, also some of them have issues with peristalsis. This might affect the microbiome as well. While it's plausible that it might help a subset of people, we should not overgeneralize since autism is a very heterogeneous condition, usually with pronounced genetic predisposition. Overall, it doesn't seem to be a cure.

I had a similar question to. From my understanding of the study, which was double blind placebo study, it does not treat autism but its shown to greatly improve symptoms of autism.

They basically wiped the gut clean with antibiotics then started treating and saw improvements.

Could be that GI issues increase irritability which makes the measured autism symptoms more aggressive but it looks very promising for families.

Not affiliated just read the study.

True that, but it could be both cause and effect. There are reports that gut bacteria can induce depression, which benefits the bacteria because it sends more calorie-rich, highly processed food down the gullet (think ice cream binges when depressed). Not hard to believe that gut bacteria optimized for a particular kind of food could evolve the ability to induce their host to eat that food exclusively. It would have the side-benefit (for the bacteria) of reducing competition from other microbes that aren't optimized for that, by starving them out. Things aren't always just cause or effect, especially in biology.