I would tell the organization what happened and ask how something like this can be corrected. However after being snapped at the first time, I would hesitate to give this program a second chance.
This is similar to the idea that someone would completely turn away from a political candidate because the staffer who organized a volunteer session goofed up how it was done. Or refusing to ever shop again at a store because a single employee was rude.
It's just sort of illogical.
I don't think the political candidate scenario is comparable- if I don't like how one volunteer program is being run, I can find another one; it would not reflect my views on the candidate. The same can be said about this meal program in the OP- this incident would not discourage me from helping others, I just wouldn't participate in this particular program anymore. I'd find another meal program that was better organized or volunteer for something else.
On the store example, just call me "illogical". If I'm going into a store for the first time and the first employee I encounter treats me badly, I'm not going back. After that first experience, I will associate that store with the rude employee and not want to risk running into them again. It also does not make me think highly of the store if they employ people that are rude to the customers. I'd rather spend my time and money somewhere else without worrying about being treated badly.