Language /does/ evolve. However, it's still dishonest to use an established term in a manner contrary to the broadly understood definition. Furthermore, the rationale for an unorthodox definition of open source is generally forwarded by those with a financial interest in their unorthodox definition, and in so doing they are asking others to work against their own interests by surrendering the mutually agreed upon rights associated with the term.

The orthodox view on open source is a useful and broadly understood shorthand for a certain enumeration of rights, the withholding of those rights disproportionately serves a certain group of interests at the expense of others, and disregarding these problems and using the terminology incorrectly in spite of them is willfully dishonest.

I disagree that everyone broadly understands the same thing as you from the phrase “open source”

Declaring words wrong is part of how language evolves.