Did I even care that the source code was visible? I have yet to contribute a patch to any of my favorite projects: Linux, Apache, PostgreSQL. A big reason is that I don't even know C or C++. But yes, come to think of it, the source-code publicity gives me comfort. At least some people are out there checking for bugs, backdoors, etc. (Right?)
Copyleft always struck me as a little weird. This article has helped me realize why. Copyleft is still based on the idea of intellectual property, and I don't believe in intellectual property. If we translate the phrase from its Latinate words to Old English, its meaning, as usual, becomes clearer: thought ownership.
In my own little projects on Github, I usually ended up going with Public Domain. It accomplishes what I want: that I and others can keep using what I wrote free of charge, that it can remain visible forever so that others might learn from and build upon it. I don't really care if a company wraps it in their little package and never lets anyone know. Also, being prior art, it should prevent someone from getting a patent on it.