I believe his extrapolation to be correct, but I'm just making some guesses about the relatively very recent history of the planet.
"I thought I said that as far new species were concerned, perhaps that part of evolution had ended, and I took a wild guess as to why."
Actually it depends on whether you use the scientific definition of speciation or the YEC definition.
The science definition of speciation is - a single population that splits into two subpopulations that for one reason or another do not interbreed and gene flow between the two groups is restricted to such an extent as to be considered stopped. This has happened on numerous occasions, both in the lab and in the wild. PatrickHenry's List-o-Links has many links to examples.
The typical YEC definition is - a cat giving birth to a dog. This is simply a strawman. No saltational event such as this has ever been proposed by science and would never survive in the wild.
Everything happens at the species level and the variance between any two related species whether in the same Genus, Family, Order, Class,... or in different classifications is a result of accumulated changes over a number of generations. We see the changes occurring, we see the split at the species level, we see the molecular evidence of larger variance.
Evolution is proceeding exactly as it always has.