This myth needs to die. Two thirds of all farmland on this planet is pasture [1] that isn’t fertile enough to grow food for humans except by raising animals on it. If we were to switch to a plant based diet, the vast majority of our farmland as a civilization becomes unusable. Most of the world uses animals to generate calories from unproductive land, first via dairy and then slaughtering the animals for food.

Not to mention, animals have been crucial sources of sustainable fertilizer for many thousands of years, without which agriculture would never have been as productive.

[1] https://ourworldindata.org/land-use