Yes, agree with the rest of the article but "open source" most certainly does _not_ include "source-available". This is true regardless of which side of the permissive-vs-copyleft issue you fall on. Being obtuse about things like this dilutes the term, which I suspect is the desired outcome. To be clear, there's nothing particularly wrong with source-available programs; they simply do not rise to the level of benefits offered by open source programs.
I'm personally not even super bent out of shape about some licensing schemes that are technically not OSD-compliant being called "open source" (i.e. ones that have targeted field-of-endeavor restrictions). There's at least a debate to be had. But what this article includes in its definition -- source code tossed over the wall that you're not allowed to do anything with -- is not anywhere close to what anybody has been calling "open source" for decades.
