I can almost... ALMOST see his side.
When I was in high school, my friends and I would have tabletop RP gaming sessions (Dungeons and Dragons) with my dad being the Dungeon Master. Because three of the players lived at our house, the sessions were held there. We provided snacks and drinks, though people often brought there own. These sessions lasted through dinner, and we switched off between providing dinner, and having people bring money for pizza... on the order of 2-3 dollars. That's where it's different. The money was reasonable for the food provided, and it wasn't a "hosted party" persay, but rather a joint get-together at the most convienient place.
So, I guess I'm saying if it was a regular guy get together, it may not be as bad to ask for a REASONABLE amount of money... but this sounds like a one-time party, which is a whole different situation.