This is certainly not what I learned to be the definition of evolution in my biology classes.

First, the article is not just proposing genetic drift, which is the change in allele frequency by chance. It is arguing that change in allele frequency is due to natural selection pressure, and that most certainly is evolution. Copied from the Wikipedia entry, because I think it's simple and clear:

> Evolution is the change in the heritable characteristics of biological populations over successive generations. It occurs when evolutionary processes such as genetic drift and natural selection act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations.

That is exactly what the article described.