Again, what gives OSI the authority to define that vocabulary over anybody else? If you want to use "open source as defined by the OSI" more power to you but I suspect most people will continue to use "open source" as "I can find the source code online".
The OSI were the people to come up with the term. Of course they get to decide what they mean.
The only argument against that would be that the term has gained popular usage outside of the open source community and become a generic term. I haven't heard or seen any argument that that should be the case.