To be fair, bike riding and swimming don't hit very hard your joints. Furthermore, you have to be very obese to receive a big hit in your joints if you're running/sprinting (using a good pair of shoes). So in other words those kind of machines are not the best tools for most of the people out there and I think that the article is about that: optimizing your time to reach your goals and free-weight training is a great option (if not the best) for the majority.