The reply device gives the donor two choices -- but both choices involve sending a gift:
Background: The letter details how the organization went ahead and gave Christmas gifts to wounded vets, even though there was no budget for that. Now they're asking donors to step up and make it good.
Of course, that's not good policy. And I have to wonder if the story is even true.
But set aside those things and consider what this piece is doing: It gives donors a "voice" while assuming that the donors fully support the goal of supporting the veterans.
Choice is good for fundraising. Even when the choice isn't very meaningful. It's like the once-common (now rare) reply device formula that goes like this:
Choice allows the donor to engage, even if she can't give. Or, in this case of this piece, to express her disapproval for a dodgy action while she gives.
Choice does its magic even when it's meaningless. It can be better yet when the choice is meaningful.