Over the past few months, we have seen competitors actively exploiting our good faith by using our open source code to compete with us directly in commercial products. On the flip side, we have received almost no meaningful contributions to our open source code.
Там есть возможность получить бесплатную лицензию как инди дев: http://www.badlogicgames.com/wordpress/?p=3762
А так же у них бабло закончилось. Оставалось вроде на 6 месяцев. Вот и продались.
Does that means once I start using the RoboVM IDE plugin, I can't compile my games on another machine without a license?
You can use a license on two machines. If you want to use it on a third you'll have to deactivate it on one of the others. Shot RoboVM a mail if you have truely special circumstances.