Who cares about people complaining to them? They would've A) Had the moral high ground, and B) Just, I dunno, received 17,000 dollars to put to good causes.
As a Christian, a D&D player, and a human being, I am disgusted.
But I mean, other Christians who do find D&D to be evil would stop donating their money. Or other people who do think that it would be wrong for them to be 'endorsing' GenCon. I'm just saying that they have to consider how it would look to everyone else, as well.