H.W.
Here's my inflammatory answer (I'm assuming you don't want me to 'play nice, or you wouldn't have asked this question in this way) : are they just *that dense* socially, or is there some kind of personality disorder/enabling codependent situation happening with these folks? In my opinion, this is beyond rude, this is "we are going to put you in your place". (Possibly borderline or narcissistic? I have people like this in my family, and passive-aggressive belittling like this stinks of their MO and how they tend to think.)
The next time they offer to bring food, you can either say "oh, just bring something for yourself" and make something your family will enjoy for dinner, or say "great. If you are going to that fancy Italian restaurant, be sure to pick up some for us. We love Italian food too." If this offends them, too bad. Their actions were beyond thoughtless-- this sounds very, very pre-meditated. You will likely "lose" either way, but at least you won't be stuck with fast food.
If you think they fall under the Personality Disorder category, and are looking for resources/support, too, there are support groups online. PM me and I can share a great one. I know I need a place to go vent and get help/advice/insight from time to time. People like this are crazy-making! And yes, sick.