It was a little more than "Cato hated Carthage."

He was a Roman Senator and every time he had a speech, he ended it with "CARTHAGO DELENDA EST!" - CARTHAGE MUST BE DESTROYED!

Even on speeches that had fuck all to do with Carthage.

It helps to understand what was going on... Rome and Carthage were on opposite sides of the Mediterranean and at odds politically and economically:

At their peak, Carthage controlled all of North Africa and parts of what is now Spain:

After the Punic Wars... yeah...

The legends of Rome literally salting the earth of Carthage to ensure permanent destruction is largely a modern myth, but yeah, they tore the hell out of it and made slaves of the survivors.

https://en.m.wikipedia.org/wiki/Salting_the_earth

"At least as early as 1863,[7] various texts claimed that the Roman general Scipio Aemilianus plowed over and sowed the city of Carthage with salt after defeating it in the Third Punic War (146 BC), sacking it, and enslaving the survivors. The salting was probably modeled on the story of Shechem. Though ancient sources do mention symbolically drawing a plow over various cities and salting them, none mention Carthage in particular.[3] The salting story entered the academic literature in Bertrand Hallward's article in the first edition of the Cambridge Ancient History (1930), and was widely accepted as factual.[8] However, there are no ancient sources for it and it is now considered legendary.[1][9][8"

It would be a little like today if, I dunno, Lindsey Graham ended every speech and interview with "BEIJING MUST BE DESTROYED!"