Well, see, I think that's what people are saying. Obviously that's NOT OKAY, big time. And the OP seems to be saying that the principle applies across the board, in all situations: hosts pay, guests don't.
But what is rude for a wedding or even a dinner party is not rude for a family meal -- not necessarily, anyway. I mean, as in the Miss Manners letter I referenced, I wouldn't tell the wedding guests to head into the hotel kitchen and do the dishes. But if my adult kids and their spouses are in town for a holiday, do they do the dishes after the big meal? Of course. I don't even think that there is anything wrong with asking the whole family to pitch in. If it's okay to suggest a potluck family dinner, it's okay to suggest cost-sharing with the same group, especially if a potluck is untenable for some reason. Remember, there's another difference between a family holiday meal and a dinner party: you don't have the same freedom of arranging the guest list. It's not "your party" -- it's the family holiday meal, even when you are the host.
It certainly wouldn't be okay to spring it even on family by handing everyone a bill at the end of dinner without warning. But if the family in the story OP read customarily divides the expense of holiday meals, then an outsider, a new in-law, or even a disagreeing member of the original group was, in my opinion, probably just trying to make trouble by calling it "charging family members for a home cooked meal."
I'll bet you anything that the rest of the family doesn't say they are being "charged." "What are we doing for Thanksgiving? Well, our family really likes to be together, but we can't take turns because only my sister Daisy has a big enough place for all of 24 of us, and we can't really do potluck because half the people live out of town or don't cook, so we all chip in for the groceries and wine so Daisy doesn't have to foot the bill for that big group a few times a year. It's enough she does all the cooking!"
Not quite so shocking that way, eh? Even if Daisy had been the one to suggest it to begin with.
Why couldn't the person in the original story simply say they don't want to do it this way anymore and suggest an alternative such as taking turns hosting or giving the alternative to do some of the cooking or bring beverages instead?