You're not wrong.

What the author means is that software maintainers need to embrace compromise instead of Stallmanesque freedom. The first he calls open source, the second Free.

I know it is somewhat jargony, but FLOSS, meaning Free (Libre) and Open Source Software, is what "Free software" means. I think that makes clear that OSS is FLOSS without the "FL." The problem (often mentioned) is that "free" is overloaded in English.