No Longer a Libertarian

In my time I've "converted" a fair number of people to the cause--or nudged them in that direction. Now I'm apparently one of the reasons a Skip Oliva is "no longer a libertarian." Ah, well, you can't win 'em all.

But what does it mean to say one is not a libertarian? To my mind, it means one does not always and on principle oppose aggression. I don't think Oliva is an advocate of criminality and aggression, so I don't understand his comment.