A credit card literally pays you to use it, with cash back or miles or whatever you get. If the price is the same for debit, why would you not use a credit card?
It's probably not a logical thing, but more like people who went through food rationing - who would never leave even a pea on their plate afterwards. On a more macro-level, you can probably see a reluctance to splash cash around for around a decade after each financial collapse.
Do you find being in a restaurant and having eaten but not yet settled the bill stressful? Or having been in a hotel room for a few days and not checked out yet? I'm not sure I'd consider a monthly credit card debt to be morally different to either of those debts. You just haven't settled the bill until the end of the stay, the meal, or the month.