You need at least some animal products to survive
You don't. The major dietetic associations say well-planned vegan diets are healthy at every life stage, and millions of people live long lives on them. B12 is the one nutrient that needs a deliberate source, and that source is bacteria, not animals.
Humans evolved eating animal foods, and those foods deliver protein, B12, iron, zinc and long-chain omega-3 in forms the body uses easily. A fully plant-based diet cannot supply B12 at all without a supplement, which suggests it is not complete on its own terms. Including at least some animal products is the simple, reliable way to cover every nutritional base without having to plan around gaps.
The body needs nutrients, not animal products. Protein, iron, calcium, zinc, iodine and omega-3 are all available from plant foods or, in a few cases, from fortified foods and algae. The Academy of Nutrition and Dietetics and the British Dietetic Association both state that well-planned vegan diets are appropriate for all ages, including pregnancy, infancy and athletes. That is a statement about survival and health, not just about getting by.
B12 is the honest exception. A vegan diet does need a reliable source, usually a supplement or fortified foods. But B12 is made by bacteria, not by animals. Much of the B12 in meat is there because farmed animals are given it, as supplements or as cobalt added to their feed. Needing a supplement is not the same as needing an animal. If it were, anyone taking vitamin D in winter would need to eat oily fish.
Personal results in the gym are real, and worth paying attention to. Eating more protein does help build muscle. What it does not show is that the protein has to come from chicken or steak. Muscle growth tracks total protein, calories and training, and studies comparing plant and animal protein at matched intakes find similar gains. More meat usually means more protein, which is the likely cause of the change.
Some nutrients are easier to get from animal foods. Iron from meat is absorbed better, for example. That is a difference in convenience, and it is managed by planning. It is a much weaker claim than need, and it is the strong claim that would be required to justify the harm.
Treating a personal story or an isolated case as though it outweighed systematic evidence. Individual cases are real, but they do not establish general patterns.
How it applies here: The speaker moves from his own experience of gaining bulk when eating more meat to a general claim that humans need animal products to survive. That single case cannot outweigh population studies and the position of dietetic bodies. It also does not separate the effect of meat from the effect of simply eating more protein.