Do you realize how many amazing works of art, literature and cinema have been made that you've loved, that have probably been written by homophobes, racists and pedophiles?
If you're going to stop playing games because they are associated with someone who is this, you better stop doing a lot of things.
The slippery slope goes far.
For example. You should never, ever read anything by Lovecraft. And you probably should ditch the classic works by Aldous Huxley.
If the only issue is you have trouble contributing -any- money to -any- homophone currently alive, then the problem is you've probably done it HUNDREDS of times and you just didn't know it. But these games are a collection of their parts. No one person represents the product in this case. Nobody anywhere is endorsing homophobia through this product.
In essence, it comes to this:
we have to accept in our gray world, where things often don't have perfect conclusions or morally "right" endings, that people who are racist and homophobic and who like to molest kids... they sometimes make great things.
They sometimes make amazing, wonderful things.
And that extends to games as well. You should do what you feel is right as it's your money, but you should also acknowledge that you are not going to hurt Orson Scott Card or send him any message he will understand. He is already highly successful, and has made good works of art. He is also a homophobe.
Thus is the nature of our dark world.