I'm ok with saying that Open Source is now widely understood to mean what the OSI says, that's just a function of how language evolves. But we don't need to re-write history to get there.

Open Source isn't a brand, it isn't a trademark, it was hijacked by OSI to enforce their specific interpretation of a phrase that was already in use. OSI wasn't founded until 1998, over a decade after the term open source software became popular and was used throughout the unix and linux communities and in businesses such as Caldera. Before OSI came up with the OSD many creators of open source software had non-compete clauses in the licence.