So you are offering your house, when you won't even be there, for this activity? AND they now expect you to provide food? That's expecting an awful lot. And taking advantage, even without the sexist comment.
Much though I would love to reply with a sermon about sexist expectations and a query as to why a group of adults can't cook for themselves, I think the best route is to reply that neither matj or mr. matj will be home. If the group would like food, they will need to bring it with them all ready prepared, as the kitchen is not part of the space being offered and is off limits during the activity. If that isn't possible, you understand why they will need to find a new location for the activity.