Not sure why you were downvoted, but this is exactly correct. "Open Source" doesn't (just) mean "You have access to the source code." It's actually a pretty specific thing.

And before anybody says it - yes, we all know that OSI doesn't have a registered trademark on "Open Source." Doesn't matter. We're talking about a de-facto definition, not de-jure. And among people who actually care about the definition of "Open Source" the OSD is the de-facto definition.

The parent is the author (but not the submitter) and is pointing to the definition that has complete concensus outside of fringe opinions (which still maybe correct: "fringe" is descriptive, not a judgement). How this comment can be downvoted is beyond me as the author's definition is surely relevant to discussion of this article.