Many people may be vegan for health or social reasons, but that doesn’t mean you should force your vegan eating habits on others, especially your pets. Cats are carnivores and giving them celery sticks and carrots isn’t going to be good for them in lieu of actual meat.
If you’re concerned about your cat’s health, simply research where your cat’s food company gets its meat. By doing a little research, you can find cat food that gets meat from animals treated humanely. It’s not the same as getting vegan cat food, but since your cat needs meat, it can give your cat what it wants without upsetting your conscience in the process.