"As for the licence, the modified MPL was chosen so that comercial projects like MOS could use the source code without having to publish their private code. Which is a good thing as it allowed the MOS guys to use and fix te AROS code without giving away their, trade secrets."
Yeah, that sounds very open source to me.
I appreciate your use of sarcasm here, but it isn't warranted. The MOS guys returned all the AROS code they used with bug fixes an a few extra features here and there... Without the MPL licence AROS wouldn't have got the bug fixes, full stop... It was a win win.
You can still make money with a GPL license. And it would really look more professional and legitimate to allow an object third party to say what the conditions are.
Selling:
http://www.gnu.org/philosophy/selling.html
AROS source code is there, you can download it, learn from it, play with it, do what you want... It will always exist in the public view, it will always be there, fork it if you like... I honestly can't see your objections in this regard. Shrug... Why waste your time arguing semantics?