Ideas can always be stolen. We've had so called investors try to rip us off left and right. Don't think Facebook isn't capable of the same.
Ideas can never be stolen. If I have an idea and tell you about it, then you use it, I've still access to that idea and can still use it too.
Yes I worked in IP for a time. Yes I'm a pedant. But there is a very important distinction both morally and legally between theft and copying (eg tortuous IP infringement).
Yeah, I'd call that stolen (or at least 'attempted theft'), because they were about to lose their rights. Thankfully, the JMRI guys won in court, so they got their rights back.