This is a phenomenon.
People who did good work and have fame are getting old. Instead of retiring they just start to do sloppy work, or fall prey to people who exploit their reduced cognitive capacity. They get publicity because internet has no editors.
Hersh is 85. He has been on decline for some time.
Remember Michael Atiyah few years back. One of the greatest mathematicians in the last century. He claimed he solved the Riemann hypothesis little before he died. It was clear that he was in cognitive decline, but media and social media had their day.