He knows his base. They won’t jab. He also has to play the game, to reduce attack vectors for his enemies. And he also knows his detractors will stay away from anything he recommends (just like that montage of clips of Dems including Kabala saying they will not trust any jab promoted by him when he was sitting POTUS) so on balance, he likely is a force for reducing jab take-ups overall. Clif High had some good thoughts on it recently - https://usawatchdog.com/biden-desperate-as-vax-narrative-falls-apart-clif-high/