Best I can tell from Plutarch, Cato the Elder was concerned that the geographic position of Carthage gave it an enduring competitive advantage in maritime trade and made it a permanent military threat to Sicily and the western Mediterranean. Moreover, Carthage was in constant conflict with Numidia, a good Roman ally. I don't think either of these factors required razing the city (nor did most Roman senators either), but it does explain Cato the Elder's beef with Carthage, against whom he had personally fought.
Thanks for the info. Any details on Cato's military career against the Carthaginians? What battles etc?