It says who they are in their signature. And a plethora of peer-reviewed papers are cited.

I guess all the people solely cheering for this aren’t aware of the damage we’ve been doing to ourselves with antibiotics:

While antibiotic resistance gets all the attention, the damage being done to our host-native microbiomes is arguably as big a threat as climate change, as the damage compounds over generations, and once it’s gone you can’t get it back. (Apr 2019).

Resistance may already be a solved problem: https://humanmicrobiome.info/antibiotics/#fmt-to-counter-antibiotic-resistance