I think you need to consider ethical questions before agreeing to work somewhere.
A few years ago I was approached by a short term loan company. They were one of those "payday loan" companies that attempts to sucker low income people into "feeling like they have more money than they really do," in the guise of "helping them." Once someone starts taking these loans, they're stuck in a downward spiral. They can't get out. Once you get it once, you need it forever.
I live in a less affluent neighborhood on the south side of Chicago, and I see this happen all the time. I think it's extremely depressing.
The company continued to press me, trying to convince me that it was a great "opportunity" and that the business was growing rapidly. Just goes to show what kind of a company they really are.
I think ethics are very important in where you choose to work. You'll be spending a lot of time there and giving them the fruit of your intellectual labor. You should do everything in your power to make sure that labor isn't dedicated to something you disagree with at a philosophical level.
If someone can "choose" not to use the product you're building, then you can sure "choose" not to build it.