Well, i mean a cockroach might be seen as being harmful because we consider them dirty, disgusting, revolting insects and we don't define insects as something we eat, at least in our culture.

蟑螂看起来可能是有害的,因为我们觉得它脏,恶心,是令人厌恶的害虫,我们不把害虫定义为食物,至少在我们的文化中是这样的

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选