one post only -
As you say, we are not far apart on certain points. However, whilst you find my suggestion that single travellers are a bona fide minority group "laughable", I must retort that your idea that families are poor and singles are rich is similarly "laughable". We just cannot generalise like that. What about multi-income families? What about widows? Ah, your husband is dead! Now you can pay extra!!! Some people are wealthy, others are not, regardless of their family situation. Ripping them off based on such a generalisation is not justifiable.
Customers purchasing identical products at the same time should not face discriminatory predatory pricing. If a manager cannot generate profit using a fair and equitable pricing structure then that individual should step aside in favour of a capable replacement. Promotional deals designed to boost bookings can be devised without selectively and unfairly disadvantaging a core group of the existing customer base. And a supposed discount on a "fee for nothing" doesn't come across as a compelling deal anyway.