Obligate carnivore means they require nutrients that on a natural diet, they can only get from meat. With processed foods, cats can survive on a plant-based diet, if the food has had the appropriate nutrition added (in a way that cats can absorb it)

Edit, it even says exactly that in the article:

While cats are obligate carnivores, complete foods like Unicorn Pate are fortified with all of the vitamins and minerals that cats need to thrive, including taurine