I'd just make a remark that even in the GPL world everything is not as simple as it looks. There are GPL versions with _exceptions_ endorsed by RMS, for example. A long time ago I used to work on a Hobbit scheme compiler for the scm interpreter, which was promoted by RMS and became Guile later. scm had such a GPL-with-exceptions clause by RMS, which was stated clearly incorrectly. I take every chance to boast that I convinced RMS to fix the error in his own GPL version for scm :)
Yes, there's a lot of subtlety to licensing. Personally I think it should be taught in computer science schools. Open source software has really changed the dynamics of corporations. Of course we wouldn't have the open source movement without free software and imho free software is more important than ever. You seemed to have struck a nice balance with this exception that protects your interests in the database space.
And yes, getting RMS to change something is quite the accomplishment :) His ability to walk the talk is impressive.