Extremely sound reasoning, followed by an absolutely insane conclusion.
Inferring from “Ideologically, the Republican establishment doesn’t appreciate the difference between being pro-market and being pro-business” to “Romney is eminently qualified to make the pro-market case” makes about as much sense as saying “Every time I eat a polka-dot mushroom I get sick. Therefore, this giant polka-dot mushroom over here is eminently qualified to cure me.”
“Ergo, presto!” as Benjamin Tucker would say.