Why should we take them seriously as a whole if they don't even know this basic history?

I'm referring to the actual use of those words in the business everyday life to refer to a business 'chart', not to the use of those words in general. Of course the words "graph", "chart" or "data visualization" did not suddenly pop up at specific moment in the recent history. In your analytics, "graph" might relate to graph theory, linguistic, or music.