Now let me say this first, I personally don't agree with Card's views on the issue however, the man is entitled to his opinion. Many may not like it, but we all live in a country where we are free to voice our own opinions. I'm all for healthy debate of opinions and lobbying on your side of the fence. I'll even support some boycotts, however I will say before you boycott something because of one person's views, stop and think about who else you might be affecting.
In the case of the Ender's Game movie, if you are boycotting because of Card's views, you aren't only punishing the author of the series. There are so many thousands of others that put a lot of time and hard work into creating the movie - actors, directors, special effects people, sound people, and on and on and on. So stop for one minute and think about how this not only affects the author (who has already hugely profited on the series), but also the many, many others involved in the project. Just think.
So am I saying don't see the movie, no. Am I saying see it, no. So what is my point here? I'm saying THINK! Everyone's actions has an affect on others and the world around them. So take one minute and think about who and what your actions may affect before you boycott something. Whatever you decide, at least you understand the consequences.