Instead of asserting the title is wrong, it would make sense to recognize that the title is correct, and that the discrepancy with your beliefs is simply a result of the fact that plenty of other people do not, in fact, take OSI's opinions as facts like you do.
The title is indeed wrong. There is no definition or usage of the word "open source" that is compatible with restriction of commercial usage.
Never in the history of free software or open source software from the release of Donald Knuth's TeX in 1979, to the birth of FSF in 1985, or the formalization of OSD in 1998 was it ever acceptable to forbid commercial usage in something that is known as open source.
The corruption of the word "open source" to mean anything with source code available on GitHub under a non-commercial license is very recent and does not reflect the true origin or meaning of the word "open source".
The implication that CC-BY-NC-SA could be open source seems to be your belief which is not based on facts.
This sounds a bit like the No True Scotsman fallacy. There is no official definition of "open source", so taking what the words literally mean, "open" and "source", ie the source code is open to view, is an acceptable definition.
To be fair, the "true origin" story is a little misleading. A bunch of douchebags wanted credit for Stallman's work and basically threw an underhanded hissy-cow to try to undermine him to co-opt his position. There was a pile of exaggerated (or often fabricated) stories thrown at the FSF. Commercial players came in to support the attack with a whole range of motives -- from wanting something more corporate to an "arm both sides" mentality to undercut the movement.
While I agree with your point, I'm not sure the alleged history supports it very well. It's a pretty ugly piece of the movement's history.
Now, that was two decades ago, those people are gone, and OSI is a very nice, good, and friendly organization today.
dataflow, I've made a few replies elsewhere in this thread that address what you said. I don't want to make noise by repeating them here, but wanted to point them out, in case you'd like to see the counterargument.
