In my opinion, the term "open source" means "the source [code] is open for people to see". You might be able to stretch that to include "and modify" but that is stretching it.
That is all "open source" really means. It's open for people to see/view. Beyond that, is where a license comes in to restrict or give freedom beyond the term of "open source". That is what OSI does. Adds additional requirements within a license. It cannot change the definition of the term "open source" however.
Open comes with the ability to participate, an open door is to let something physical through, not like a transparent window that lets one see, an open market, open auction, or open sports league explicitly implies more than just viewing the activity.
For many of us, we've never used "open" to mean viewing.
Right now I wouldn't trust the license to let me message my boss or buy something from a store on my personal phone without violation, commercial activity is an extremely broad term.
That is all "open source" really means. It's open for people to see/view. Beyond that, is where a license comes in to restrict or give freedom beyond the term of "open source". That is what OSI does. Adds additional requirements within a license. It cannot change the definition of the term "open source" however.