The critical word is "voluntary." It is not generosity if it is compelled.
Many leftists believe that people should be compelled to "pay their "fair share"" under compulsion by the government, but they are not voluntarily generous enough to give more on their own (which they have every right to do.)
What is your definition of "joy"? The definition here is the inward satisfaction and contentment that comes from the confidence that I and many others have which comes from our worldview of Christianity, capitalism, and voluntarism.
