The Red Cross receives funding through donations and/or government subsidies. The donuts really are not their core product, if anything they would be more akin to a retail 'loss leader'.
The average web startup only has one core product, at least it gets to the Facebook scale of having thread its way into multiple aspects of your life. These startups are only getting their money through venture investors, who most certainly do not view their checks as 'donations'. So, there is a basic requirement to transition from free to revenue generation in some fashion.
The troops most likely saw the donuts as a small token offering from the Red Cross, and also felt they had done something to earn these free donuts. While there is a lot of feelings of entitlement among some customers of free services, I think the bulk of the users understand the company has to make money somehow.
In many cases the 'freemium' model appears to work well, as long as the paid versions offer obvious value. I wouldn't recommend for most people to not offer some free version of the product, but I also wouldnt warn them against charging for their products via a story about Red Cross donuts.
Understanding and caring are two completely different things.
More importantly, when the fee was removed again, parents continued late pickups at the higher (with-fee) rate. That's the real point of both stories - once the terms of the agreement have been moved from the social to the monetary realm, it's very hard to get people's brains to switch back to the social terms.
Then when you remove the price you are sending another signal, which is "oh it used to cost money but now we offer this for free!
It's worth really thinking through the whole social signal thing first....
with the Red Cross, one option might have been a donation box right next to the donuts with a note saying what they had been asked to do and why.... and soliciting additional donations, to be used to provide donuts to the British soldiers, perhaps! That avoids changing the relationship.....
If the Red Cross had shut down the donut stations and then came back some time later with comfort food in a modified form, the soldiers would see the new stations independent of their anchor to the previously free stations.
Indeed, the fault lies with SecDef for the change. And the change affected a certain aspect of morale. But the suggested change would most certainly have been noticed. If Red Cross was the only place to get this item, then it dried up, then someone else made them available, even at a pittance, the entitlement sentiment exists and colors the experience.
Are these services really free? We may not pay cash to use these services but we certainly are paying something.
But that's not the point. The soldiers perceived the donuts as free, and people perceive Facebook as free. Charging for donuts or access to your wall will change that perception.