Why do commentators say things they know aren't true?

Like in the Pacquiao - Barrera rematch, Lampley said something like "don't forget Barrera knocked Pacquiao down in their first fight". Everybody knows it was a slip, he should have said that. It's like he got excited and tried to make it more than it was. He and Kellerman have also said on occasion that Calzaghe was down against Eubank, when it was the other way round.