Lizzie/Camila: I agree w/ you both. If you think about it, there are really TWO stereotypes in play here: the one that's explicit, namely that women belong in the kitchen, the other implicit, namely that men don't know how to cook and so should stay out of the kitchen and leave the cooking to women. Both are incorrect and sexist and duo should be made aware of it.
I imagine the point here is that everyone's seeking consistency where there isn't any. No language is fully logical/consistent, and Italian is no exception to this rule. Just keep plugging away, and in time you will pick up the rhythms and world-view of Italian. Prepositions are always the peskiest part of learning any language (I've learned Latin, French, Russian, German, Hebrew, and now Italian, so I think I can say this with some certainty!).