I don't think that's the author's fault. The truth is "Socialism" has always been ill defined. By the definition I was originally taught (a society where Government intervenes in the private industry to mitigate inequality) the U.S. has been socialist for my entire life time.

That said, you took that quote out of context. The real focus of it was on "welfare state" and it was presented with the fact that the Food Stamp program is adding 20,000 new people each day. If that's true than he's right about us quickly becoming a welfare state.