Of course it is naive - his business is built around it. OpenSourcing takes a lot of revenue away from him. Compensating that with support contracts and cloud services won't be easy.
Not to mention the fact that probably he doesn't own all rights for doing that. Software with such a history often contains third party licensed modules.
His response belittled the question, calling it naive. His smugness was astoundingly tone deaf.
Until he figures out how to answer questions like this without using shame to cow developers into line, I’m staying away.