Orson Scott Card. Homophobic asshole, but I still like his books.
I remember when the Ender's Game film finally became a thing, and the boycotts began. Someone on the internet, I think one of the TGWTG crew, made a blog talking about how we shouldn't boycott the film because it'll ruin the careers of the non-Orson Scott Card people involved in it.
I speak as someone who actually acts professionally (I make money from it), and someone who's been part of film productions. If I was given the chance to be part of the movie, I'm divided on what I would do. It's an extremely prominent Hollywood film, and networking is the most vital part to a successful acting career. I've gotten closer to living the dream simply by going out and working in the business than I ever did while trying to get through college as a theatre major. At the same time, my own personal beliefs regarding civil rights would leave a bad taste in my mouth if I willingly participated in a project that would give profit and prominence to such a hateful, backwards man.
In the end, you act at your own risk. People talk about the crew, but those guys are going to be fine; unless we're talking something like a remake of Birth of a Nation, nobody is going to give the crew and production team a hard time for their project. Electricians, script supervisors, and camera operators will always be able to find work regardless of how bad one of their big projects tanks. But for an actor, every project you take is a major risk. Even if you get paid millions up front and become independently wealthy from that single project, one slipup can ruin you. Sometimes that's a risk you have to take. But sometimes it's a risk you should acknowledge and avoid.
I don't feel bad about refusing to see Ender's Game (or at the very least, refusing to pay for any Orson Scott Card product). The boycott against the film began where there was barely anything but a teaser trailer available, and his loud stance on homosexuality has been well known for years before then; nobody should have gone into the production blind regarding what backlash could have occurred (and did occur).
And in reality, it seems like nothing actually happened to ruin anyone's careers: almost all of the actors had established careers (yes, even the kid playing Ender), and the director probably got more shit for X-Men Origins: Wolverine than he did for Ender's Game.