It's basically the word for word consensus advice of decades past. At least two generations grew up in a world where "take out the biggest mortgage you can" was considered good advice by default. As history has proven that is not a consistently successful approach for individuals and has some pretty severe trade-offs at the societal level. I'm not sure if it was the point he was trying to make but in any case it should probably serve as cautionary tale that consensus is not necessarily correctness.