"...she bit her lips shut - blood trickled unnoticed down her chin - and drove the sled in silence." (p. 691)
If Evalyth does not notice the blood at the time, then should it be mentioned in a passage narrated from her point of view? The other way to impart this information is to tell us that she noticed it later.
Evalyth still drives her gravsled in pursuit of her husband's Lokonese murderer, Moru. See here. When she finds them, Moru, his wife and two sons resemble grotesque gnomes. Their appearance makes it easier for her to loathe them but this is not morally relevant.
Another fact is relevant. The Lokonese do not merely believe but know that their sons must eat human flesh if they are to become men. This is not a superstition to be condemned but a condition to be cured. Problem solved.