There is a public service in these flights, they maintain a living heritage and act as a homage to those that were involved in their use. Whether a B-17 or UH-1, the risk that is imposed to the individual is a personal, accepted risk, it is necessary to be informed but it is the individual's decision, like parachuting... and the risk to others is manageable with any reasonable planning.
I'm not sure I fully agree with that: yes, there's a public benefit, but the risk of flying on such an aircraft as a member of the public buying a ticket, is different to that of a parachute jumper. The aircraft operator bears the full responsibility for ensuring the aircraft is operated correctly & to the standards required - the buyer of the ticket can only base their decision to fly on that expectation, they don't have the facilities, qualifications or experience to understand whether that confidence is misplaced or not. The solo parachutist takes that risk upon themselves, in the knowledge that the equipment is correctly made & maintained - the jump is under their control, in so far as that is possible. The aircraft passenger has no control, & therefore the operator has an obligation to make sure they manage those risks appropriately. The fact that we, as aviation professionals, may consider that a higher risk than for a normal passenger flight, makes no difference: to the man on the street, their expectation of safety is the same.