Humans would get distracted by the statement. Moving from a pure-math context to a cat-facts context and back has context switching costs, and depending on the exact setting those can be quite relevant. If it was an academic test some people might even get stuck on the cat part, wasting lots of time trying to decipher what role it plays

And the paper isn't just adding random sentences, it's primarily about engineering the most distracting pointless facts to add to the problem. That would absolutely work against humans, even if for humans the exact sentence might look quite different