One one hand, this seems crazy if the software created is given -- for a bad metaphor: imagine a charity being unable to feed people because those people may use the energy they get from that food to do non-charitable works.
Separately, and to play devil's advocate, I can kind of see the logic here: it creates a loophole through which re-usable work that is funded under tax exempt status can then be used by anyone, so you could imagine some org donating some money to get some particular work done, then getting it and using it without having to have paid tax on the equivalent work that would have been done if they paid for it. Going back to the food metaphor, it might be like a charity offering free food to anyone, rather than just to those who have a particular need. I think that such a charity might run into a similar rejection, but I don't know.
Like I said, I think it sounds crazy, but hopefully this draws more interested parties into the discussion.