> Animal protein is healthier than plant-based protein.
All commonly consumed sources of animal protein (meat, poultry, fish, eggs, dairy, etc.) are complete proteins, meaning they provide all essential amino acids. This is not true for all sources of plant-based protein. In addition, "protein" as is often used to indicate a part of a meal (I mean not just the technical definition of a chain of amino acids). Vegans are nearly always advised to supplement with B12 because good plant protein sources like legumes are poor sources of B12.
I understand what the study is getting at with the question, for as far as I am aware there are no studies that show that getting, say, 10 grams of complete protein from animals is any different from getting 10 grams of complete protein from plants. Still, given this question is easily ambiguous for valid definitions of "healthier", I find this study suspect, despite having no problem with the general idea that tons of people believe absolute batshit insane ideas about health and nutrition.