John Galt, I should hardly have to explain to you that some small number of people simply hate free markets, and a much larger number have no idea how they actually work.
I'd say it's more an attitude of entitlement. "The airline used to give you $200 to rebook, now they give you less!" As if the airline owed them the opportunity to take the next flight.
If anything this will allow the airline to overbook much more aggressively. Giving people the opportunity to take that money more often, and if anything make more than the old method overall. Of course when that happens the story will change to "The rich get to travel whenever they want and the poor are stuck waiting!" Or "Ticket speculators are increasing ticket prices so the poor can't travel!"
There once was an airline which operated under those principles. PeopleExpress, Bus of the American Skies, used to line people up and simply ship them off on the next available flight. People could (and would) jump ahead in the line by paying someone ahead of them to switch places. You had to pay additional fees for everything except your seat.
Like all a rabid experiments in brutal capitalism, PeopleExpress went bankrupt.