A post on X claimed to be a simple message from the U.S. Department of Health and Human Services: Stay active; eat well. But the 90-second video it shared, called “Secretary Kennedy and Kid Rock’s Rock Out Work Out,” seems designed to be bewildering. Here was Robert F. Kennedy Jr. eating steak and doing preacher curls in his belted blue jeans and a pair of hiking shoes; and here he was again, stripping off his T-shirt to ride an exercise bike inside a sauna; and here he was a little later,