I don't write (or publicly release) much code but I truly want anyone to be able to do whatever they wish with it (whether the result is open or closed). Unfortunately, the GPL doesn't allow that.
I think a World full of closed source software would be dramatically worse than a World full of open source software. This is why I love the viral nature of the GPL.
Of course, the chain can't end with me and I'll have to publish my own changes. But it's worth it, I'm not a proprietary software asshole, and in the end I'll benefit from other people's changes and insert it back in my own code and improve my sales that way. You, me, the other programmers, Stallman, the users, everybody wins!
That's how I see it anyway. In the end, you have your own priorities and if you like to give without always receiving, that's understandable too. Ah, tradeoffs...