To understand the GPL family, here's a rule of thumb: they try to ensure to freedom of the software user, not the software developer. The GPL restricts the freedom to restrict freedom. It goes out of its way to ensure users retain their freedom when using software, including the freedom to see the source code and modify it. In interviews, RMS often talks about his frustrations as a software user. From this point of view, the GPL makes more sense. This is also why the GPL is constantly being updated to fix "bugs" which publishers exploit, to circumvent it (TiVoization, SaaS, something else will surely follow).

MIT/BSD, on the other hand, are about developers. They let me, as a developer, do what I want, including restrict my users. This is why they're popular among... developers! :) But if you look at it as a user, it's actually not ideal.

This is a gross oversimplification, but I find it helps put things in perspective. YMMV!