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).
They’re clearly not talking about the benign strains.
I agree GP is being silly though.
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.
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
Is curiously a double true. Either way you take it, there is always a possible interpretation that leads to a logical, non-satirical meaning.