Must be my extra couple of years then, as I have been to a wedding of a lovely couple I know who let us know they couldn't afford an evening buffet, but that we were very welcome to join them in dancing the night away if we would like to. It was a lovely evening, celebrating / partying with two lovely people. Of course, it was only an invitation so if I were so easily offended as the OP, I would have chosen not to go.
Point being, at the wedding the OP went to, she actually was offered food. It is jst that she was rude enough to then start criticising the food that the B&G had chosen.
whilst spending a small fortune attending a close family members wedding..
I'm unclear how / why it "costs a small fortune" to attend this wedding ? 
If you can't afford any more change venue/save until you can
How rude. Why should someone postpone getting married for a year because they have a rude and ungracious cousin they felt obliged to invite ?
Sounds very sensible to me, to cut your cloth to suit your budget.
How about 'If you can't get through an evening party without a 3 course meal, then feed yourself beforehand' ?