The book The Fat of the Land by Vilhjalmur Stefansson (https://en.wikipedia.org/wiki/Vilhjalmur_Stefansson) describes how the Eskimos he lived with ate rotten fish all the time. It was a delicacy for them.
Kind of like we eat "rotten/spoiled" blue cheese and dry-aged beef.
But yea, it seems our digestive systems can adapt to it pretty well, given that we've been doing this since long before doctors were around. I suppose the acid kills all the bacteria in the rotten meat unless you're super weak immune wise.
Not just that, there are toxins lethal to "normal" humans (i.e. cadaverine) that one can adapt to by eating small amounts as a child.
Chukchi babies would get ever more rotten bones to suck on (i.e. pacifiers) presumably for that purpose.