Well said, sir!I think this author's thesis fails because of terminology. His argument contains an unargued and hidden premise—namely, that to say a theology is "Augustinian" is to say that it matches Augustine in every particular. (By the way, Augustine doesn't match himself in every particular in a lot of cases. It is often difficult to say "Augustine believed X" about something, and anyone who tries to do so is hardly engaging in sophisticated historical theology.) That's just not the case, though. Calvinists are most certainly Augustinian in that their theology, in large part, is a revival of Augustinian soteriology. Sure, there are modifications and corrections (think of Calvin's correction of Augustine's conflation of justification and sanctification), but that doesn't mean that Calvinism is not, on the whole, Augustinian.
In the end, though, who cares? I don't mean to sound crass, but these bloggers often write as if disconnecting their opponents from their self-asserted theological heritage will somehow discredit or damage them, as if what matters for orthodoxy is genetic theological descent and not fidelity to Scripture. My convictions do not depend on whether some Lutheran thinks I'm Augustinian or not.
If Calvinists aren't Augustinian, then Lutherans aren't Lutheran.