The problem was not that we understood terms differently.
We may have done, and it may have produced obstacles to communication.
However, the problem with the conversation was that the other participant made hasty assumptions, and was predisposed to attack, rather than being reserved in judgment and willing to discuss. Ironically, such eagerness led to attacking me on the inferred basis of my discussing in bad faith.
Such kinds of smug dismissals contribute to toxicity in communities. They obstruct both explaining and learning.