Thanks for all the replies.
It is true that the illustration is flawed. It does indeed represent the narrow thinking of JW's. It is simple and inaccurate. With just a slight amount of critical thinking, it can indeed be debunked.
But, it is often used by THEM to illustrate that there should be NO tainting from "satanic or worldly" sources.
That's why it came to mind.
I am simply thinking that it may be helpful to use on JWs who try and justify the many "corrupting" elements that the Society is and has been involved with.