They’re clearly not talking about the benign strains.
I agree GP is being silly though.
On the other hand the immune system selects for beneficial bacteria, which take up space and nutrients so that really harmful ones can't colonize: https://sci-hub.se/10.1038/nri3535; https://www.nature.com/articles/s41586-022-05141-x
Enterotoxigenic Escherichia coli (ETEC) is a type of Escherichia coli and one of the leading bacterial causes of diarrhea in the developing world,[1] as well as the most common cause of travelers' diarrhea.[2] Insufficient data exists, but conservative estimates suggest that each year, about 157,000 deaths occur, mostly in children, from ETEC.[3][4][5]
https://en.wikipedia.org/wiki/Enterotoxigenic_Escherichia_co...
The most common sources for Shiga toxin are the bacteria S. dysenteriae and some serotypes of Escherichia coli (STEC), which includes serotypes O157:H7, and O104:H4.[4][5]
Symptoms of Shiga toxin ingestion include abdominal pain as well as watery diarrhea. Severe life-threatening cases are characterized by hemorrhagic colitis (HC).[15]
The toxin is associated with hemolytic-uremic syndrome. In contrast, Shigella species may also produce shigella enterotoxins, which are the cause of dysentery.
Is curiously a double true. Either way you take it, there is always a possible interpretation that leads to a logical, non-satirical meaning.
Except in a tiny number of cases it is unpleasant but short and not threatening (remember to drink a lot, though, the most dangerous effect is dehydration).