Even then.

Even then what? If the cycle continues where you’re continuously slaughtering and replenishing the animals for food and not letting them live their natural life, the argument that it is better at carbon capture is moot.

Same argument works against the OP. Who cares if their meat is from captured carbon, if all meat has always been?

Because one (animal agriculture) emits way more carbon than it captures. That's what the article discusses - people trying to make a source of meat-like protein that emits no or negative carbon into the atmosphere.