Twitter is free to invent whatever narrow definition of shadowbanning they want, and we are free to call out their obfuscation for the bullshit it is.
Language is about effective communication. Right now we're all trying to have an important conversation about relevant social issues which requires a common understanding. You cited the common understanding, I pointed out how Twitter engaged in practices covered by that common understanding, and that should be the end of that. Can we move on now?
Instead of bikeshedding over this irrelevant minutae, engage with the actual substance of the discussions, like whether they should shadowban in the way they've been doing it, whether there should be limits to moderation policies for online public squares, what the guidelines for censoring speech should look like, whether to deplatform people entirely or merely deprioritize their speech, etc.