Let's turn this on its head for a minute; let's boycott Chris Sprouse for his intolerance of other people's views. That man should never get work again. Right?
That does bring up an interesting point, though. How does DC really feel about Sprouse doing this? Sprouse just showed himself to be unreliable and willing to leave his publisher in a lurch based on whim. Is this someone you give more work to? Can you depend on them? Sprouse has been highly unprofessional here. If he didn't want to work with Card in the future, then that's fine; but to back out on your commitment to drawing an inoffensive story? I wouldn't hire Sprouse again.
DC probably should've never hired Card to begin with, at least not for one of its flagship characters. But I'll agree that what Sprouse did was highly unprofessional and he should suffer for it as well.