I have to disagree with that. If the PnT shows are documented history then you have a point. But virtually all are merely unsubstantiated opinion and/or Pray for Pay.
That's a pretty rigid definition for "educational". I doubt that PBS could live up to it, either. As for unsubstantiated opinion, I'm not sure where you got that idea. Most TV preachers are solidly Bible-based. You may not agree with their source, or the conclusion they draw from it, but I can say the same about other NCE programming.
Dr. Gene Scott, OTOH, he was waaay out there. Entertaining as could be (his older stuff, not so much the newer stuff he was doing before he died), but waaay out there.