> However, you don't need to be 'ok with the BSD' to be ok with this. Your code, with copyright assignment, is still GPLed. It just has another license. That doesn't take away the freedoms of the GPL, it just allows other people - that prefer to do so - to get it under that other license.
No, this is false, it could take away the freedoms of the GPL (the freedom which the GPL assures). What makes you believe that this cannot be the case? What would guarantee that this would not be the case?
If I write code and submit it to a project with copyright assignment, and they chose to release my code with a non free license, receivers of that code may, or may not benefit from the freedoms which I want them to benefit from, freedoms which the GPL assures them. There are many situations where this could be the case. A simple example would be: if they combined my submitted code with proprietary code and distributed it disallowing modifications. The receivers of that software would not have the legal ability to modify the resultant work (not even the sections which I contributed), they would have lost that particular GPL assured freedom.
> But, if someone wants their code to be GPL, but *doesn't* mind additional uses of it, then they would be fine with copyright assignment.
This is true. But it seems unlikely that someone would take that stance, since there would then be no additional benefits of the GPL over the BSD license then. It is extra effort to chose the GPL, why would somone chose it only to have it be subverted? Obvisouly, they may do so, there just doesn't seem to be any incentive to do so. Can you suggest one?