It is a generous act but it comes at no additional cost to the donor and what person doesn't want their work to be as useful to as many people as possible?
I believe it is also the key thing to consider in explaining the rise of software piracy and the opposition to DRM. I hope to see a complete paradigm shift in my life-time, in the everyday software-user, in understanding what what they can reasonably be expected to do with a digital work, i.e. copy, copy and copy again as it doesn't cost anyone anything.
A business with an 85% percent profit margin makes me uneasy and seems exploitative to say the least. It is unfair to the consumer, it's just that most consumers don't really know or care, they can always pirate it if they can't afford it.