I agree with you David! You went above and beyond out of your way to be kind to the travelers - offering them food they are familiar with. You did this entirely out of the kindness of your heart, and to have them cavalierly brush it off is horrible.
I am pretty young still (mid-twenties) but I would agree with you that manners are becoming more and more scarce. It seems to me that parents are not teaching their children how to be polite anymore - I can see it in my students as well as in the college kids that I work with over the summer in my summer job.
My mom used to make my sister and I sit down and write thank you notes at birthdays and Christmas - we hated it then, but now I am glad that she taught us to do that. I now write thank you notes to all my students who give me a gift. Most of them are flabbergasted - they've never heard of such a thing!
I'm sorry that your lunch and kindness was overlooked - hopefully the travelers from China appreciated your efforts more than the youth pastor.