Possibly. But if so, they do that for a simple reason: "Upselling" past donors will in most situations have substantially higher conversion rates than obtaining new donors. It may not have been cost-effective in his specific case, but it's likely a cost-effective use of their resources on average.

But it's a bait-and-switch. The donor expects that their $50 contribution will be 90%+ spent on the cause, but it's not.