I don't think that's exactly his position. His conclusion was that it was fine for them to believe that evolution happened, but that it was a leap of faith to believe it based on evidence in the Grand Canyon. I don't know enough about geology to understand the specifics, but I know that there are other sources for the information I cited, and I'll keep looking for them.
I think the whole point is that it takes as much faith to believe in evolution as it does to believe in Creation. Much of science refutes the possibility that something came from nothing, but scientists believe it happened anyway.
Your earlier point that it should be taught as theory is key. It's not. It's taught as fact, and those who don't believe it ridiculed. To believe everything that atheistic scientists claim they have discovered regarding the so-called 'missing link' is a dangerous trap that even Christians can fall into. They (the atheists.....not all scientists) have an agenda, and that agenda is to propagate a disbelief in God.
IMO, the 'theory' of the Creation and the Flood, and the theory of evolution both need to be taught in public schools as scientifically valid, but not provable choices from which students can draw their own conclusions.
For many years geology was based on the belief that all landforms and the progress of evolution were in a gradual, uniform step. This was called The Theory of Uniformitarianism. The idea was that processes observable today were also observable in the past. In other words, if one could see silt deposited in a dust storm, it was safe to assume that in the past the same process would deposit silt.
As more evidence becomes available, it is becoming evident that there are times in the earth's history in which catastrophic events shape the surface of the earth. An example of this is the Washington Scablands, in Washington State, which are now believed to have been formed by the breach of a natural dam of a huge, glacial meltwater lake, in which billions of gallons of water swept over the plains west of the Rockies and formed a scoured, bizarre landscape while rushing to the low elevations. A modern example of this would be the devastation around Mt. St. Helens.
The current theory is that the evolution of the earth's surface is caused both by consistent, everyday processes (spring floods, sandsorms, stream erosion, beach deposition) and the odd but devastating catastrophes which shape landforms as well (catastrophic volcanic explosions, breaches of natural dams, comet, meteor, and asteroid hits, etc.).
No one with any scientific credibility believes that the earth was formed solely by catastrophic events.