GPL, BSD, Opensource/Free Software movement.

I've be a mindless supporter of these movements for years now not because I was a developer myself but because most of them provided me with a lot of useful free software.

However now that I'm becoming more of a programmer I'm questioning the ideology behind these movements.

1. For which situations are these intended? For every developer?
2. Doesn't it go against the developer himself? How can he secure profit while still sustain such projects?

Just willing to learn.
Thanks.

When you are no longer distributing the software, you don't have to make the source code available.
If you distribute the software in binary form with an offer to provide the source code, you have to keep the source code available for 3 years after you stop distributing the software.