I think the point is that you describe what John does, or how people think of John, rather than what John "is". The Wikipedia article (which constitutes all I know about E-Prime) says:
> [The authors of E-Prime] describe misuse of the verb to be as creating a "deity mode of speech", allowing "even the most ignorant to transform their opinions magically into god-like pronouncements on the nature of things".
> [The authors of E-Prime] describe misuse of the verb to be as creating a "deity mode of speech", allowing "even the most ignorant to transform their opinions magically into god-like pronouncements on the nature of things".
And I think that's appropriate here.