You might look the documentary, which gives a balanced view concerning the practice : it is explain by a vet why the anatony of a duck allows it : it can swallow a big fish alive without problem. And the goose in the french farm seem not traumatized.If it is made reasonably (a too much big liver is bad quality).
It is Ok to eat meat for survival but eating meat for pleasure is cruel and unfair to animals.
That's the big gap between surviving and gastronomy. There is many things in our alimentation that we don't need : drink, sweeties, spices, etc. But I doubt we could come back to Paleo meal. Even the current Paleo diet is a fraud. I read in a book of Paleo recipes : Paleo muffins, Paleo waffles

And they use oils, while Paleo humans did not produce it.