That doesn't make sense. If they buy the competitor, why would they tank the business which is now their own instead of gaining the combined revenue and market share?
"Buy and trash competitor" isn't a real strategy. When an acquisition fails, it's usually poor management or vision, or just a lack of synergy in the first place, not a purposeful tanking.
Meanwhile, they basically invented the "buy your competitor and tank their business" strategy. That's probably what this person is referring to.