Yes but they had other jobs to do.
If I was transported to Voyager in the Delta quadrant I'd end up a cook too since I couldn't do anything else. I couldn't even teach Naomi since I wouldn't know any Federation history or the maths etc.. I'd be like well... vegetables. Vegetables I know. Sure most of them are very different vegetables but just let me have a taste and I'll figure out what to do with it.
Imagine if you took someone who knew no earth foods and gave them a bunch of vegetables. They might make some interesting assumptions. They might use carrot puree as a basis for lots of soups whereas you would think potato was a more obvious choice. That kind of mixing around what quantities we normally think of as making a balanced dish.