Evaluating the harm from closed source
Some people are obsessive about never using closed-source software under any circumstances. Some other people think that because I’m the person who wrote the foundational theory of open source I ought to be one of those obsessives myself, and become puzzled and hostile when I demur that I’m not a fanatic. Sometimes such people will continue by trying to trap me in nutty false dichotomies (like this guy) and become confused when I refuse to play.
A common failure mode in human reasoning is to become too attached to theory, to the point where we begin ignoring the reality it was intended to describe. The way this manifests in ethical and moral reasoning is that we tend to forget why we make rules – to avoid harmful consequences. Instead, we tend to become fixated on the rules and the language of the rules, and end up fulfilling Santayana’s definition of a fanatic: one who redoubles his efforts after he has forgotten his aim.
When asking the question “When is it wrong (or right) to use closed-source software?”, we should treat it the same way we treat every other ethical question. First, by being very clear about what harmful consequences we wish to avoid; second, by reasoning from the avoidance of harm to a rule that is minimal and restricts peoples’ choices as little as possible.