Never saw that textbook and would've raised a little hell about it if I had.
Regardless, we don't throw out a valid scientific principle because some yahoo misapplies it. What you're describing above shows a fundamental lack of understanding of the concepts of race and evolution. That text implies a linear evolution from a common ancestor through all races -- that isn't how race works. It's a divergent principle -- from a common ancestor group, different, isolated groups develop different characteristics simultaneously, not in sequence. The text would only be remotely valid if each racial "step" stopped evolving, which simply isn't the case. There may be some common ancestor from Africa for all races, but the people of Africa today will have diverged genetically from that ancestor just as much as those in Scandinavia or China.
And again I have to point out that the people who see the differences and treat others negatively because of them don't care about the legitimacy of the science, so they'll misuse the concept of evolution to come up with crap like that to support their point -- through either ignorance or malice. They will use every study in a twisted way to justify their beliefs and actions, regardless of the facts.
It's a statistical fact that there are more blacks than whites in prison in the United States, despite there being more whites than blacks in the overall population. A racist is going to take that study and argue that blacks are predisposed to be criminals, despite the fact that there's nothing in the study to support the claim. So do we not do the study, try to determine the cause and address the societal and cultural issues that cause it just because the data is going to be misapplied by the ignorant?