Okay - So reading through that I get two impressions. They can't release source code because they use proprietary hardware. Secondly they believe that security through obscurity is better than publishing the code for everyone to see.

I doubt they keep it closed as a (dubious) security measure. Likely they believe the source gives them some sort of competitive advantage. (Not saying they're right or wrong about that, just that's likely what they believe.)

Wow... I've never read so much bullshit in one blog post. They're basically hoping that nobody who reads this has any embedded development knowledge.