And veganism is about living a lifestyle that causes the least amount of suffering. And not solely about not eating animal products. (Cultivated meat can be considered vegan, if it has been produced ethically and no animals or humans suffered) Not giving your cat meat causes suffering so is by definition not vegan.

Side note: Veganism is also about reducing human suffering so cocaine is not vegan. Just a reminder to vegans who use cocaine. Met a bunch of those last week.