Offit is on the FDA's advisory panel VRBPAC. ACIP will do a cost benefit analysis for all ages on Tuesday and discuss the matter when they make their eligibility recommendations for the vaccine. There's a lot of reasons for younger people to get the vaccine, and more centrally many people aren't aware of their health status. And the most relevant cost of coronavirus vaccination- myocarditis- is rare and quickly resolves without treatment.
I think these statements just increase public confusion, especially before even looking at the data.
He's consistently focused on severe disease and death this pandemic, but there are other considerations for public vaccination.