Well sounds like they are the rude ones...... but obviously you cant be flat out rude back...
But there are some people you just cant make happy with your decisions. If i were you there are 2 ways you could go about it
a. Take your own food and be peaceful
b. do a hunger strike while there to show them you dont appriciate it at all and also that what they say is hurtful
personally id do B but thats because that would be what my fam would have to see is my health in danger to stop messing with me, but its MUCH more respectful to do A lol

hope that helps!