You can't have it both ways.

You can't have it both ways.

"To my understanding the additional permissions are not there to address new ethical questions, but simply to make it easier to distribute software using code that is licensed under a free but GPL-incompatible license. (such as the CDDL, which would allow for GNU/Solaris)"

I basically agree with everything you said, but it's worth noting one thing here: If the point of allowing additional permissions is to make it possible to combine code with code written under other, more permissive licenses, it's important to note that removing those permissions removes the ability to make that combination, so a downstream redistributor would have to strip out any code that was no longer compatible with the more restrictive license.

I think the whole question of compatibility and of distributing mixed-license code is under-addressed in the license and in licensing discussions in the community.

The FSF site says a license is GPL-compatible if it allows distribution under the GPL. That's somewhat misleading. The code [in most cases] remains licensed under its original terms. The compatibility is that the terms of the other license are not violated by distribution under the terms of the GPL - you're still distributing the included software under the terms of its own license, because those are the only terms that allow you to distribute it.