This is not only a privacy concern (in fact, that might be a tiny part since the code might end up public anyway?). There is an element of disclosure of personal data, there are ownership issues in case that code was not - in fact - going to be public and more.

In any case, not caring about the cost (at a specific time) doesn't make the cost disappear.

The point they are making is, that some people know that, and are not as concerned as others about it.

Not being concerned doesn't make the statement "it's free" more true.