So the car manufacturer is responsible for the thief stealing the car? I don't think the comparison to the rape victim applies here. If somebody chooses to jump into an abyss, it seems fair to blame them for the consequences.

I thought about it before your response, and I admit, there is that one way by which I might help people receiving bad software: by not using GPL I support a world in which unfree software could possibly exist.

However, for myself it seems sufficient to work towards a world in which everybody has the opportunity to use free software if they want to. Suppose I would be giving away free cars - a thief could still steal a car, but since he could just get one for free anyway, his incentives for stealing a car would be far less. Creating a world in which nobody would even be allowed to create unfree software seems unnecessarily restrictive to me, and in fact, undesirable. By consequence other possibly dangerous things would have to be made illegal, too. Eventually the whole world would be Disneyland - not something I would want.

Edit: to clarify, I agree that some of these things are personal preferences, so I understand how choosing MIT license is a political decision, too.