I don't really see how anyone could mistype "people" instead of "pepper", - unless it was some kind of Freudian slip - and since both would be recognised by a spellchecker as legitimate words I don't buy that explanation either. If the first or the second "p" of pepper were to be mistyped with an "o" an English language spellchecker would suggest "pepper" but would not suggest "people".
I can understand that some layout artist or typesetter thought it would be "funny" to replace pepper with people and having done so it got through whatever proofing process followed.
It would not be the same issue if the recipe had called for white pepper and this had been "mistyped" as "white people" in part at least because of the history of the relationships between black people and white people in Australia and elsewhere. And that's why the original error is offensive and the response of the publisher more so.