OMG Tucker Has a "Worry" About the Non-Aggression Principle

Jeff Tucker writes at Liberty.me:

St. Thomas Aquinas wrote in passing on the subject of law that it should be limited to punishing stealing, killing, and such like. I always thought that was a pretty good summary of the nearly universal conviction concerning public morality. Of course he didn’t apply this rule consistently (in another place, he thought killing heretics was a great idea).

Libertarianism didn’t come up with some new and unusual moral theory, something unprecedented in history that requires careful discernment and teaching. What makes it unique is that it consistently applies an intuition to public life and brings it down against the state itself. If you want to call that the non-aggression principle, I’m fine by that but I don’t think it’s really necessary to codify it to that extent. Sometimes I worry that the NAP comes across as something weird and unusual when it really is not.

How exactly does the non-aggression principle come across as something weird and unusual?  As Walter Block puts it:

It states, simply, that it shall be legal for anyone to do anything he wants, provided only that he not initiate (or threaten) violence against the person or legitimately owned property of another. 

What is Tucker's problem with this? What is weird about this? Is he moving away from NAP?

Further, it should be noted that Tucker's writing is sloppy here and he gives the impression that NAP is a complete moral theory. He may be doing this so that he can add further moral appendages to NAP and introduce, down the road, a new broader term for NAP that includes other moral appendages.

It should be noted, though, that NAP is only a subcategory of greater moral theory. Murray Rothbard explained it best:

[Libertarianism]  is not and does not pretend to be a complete moral, or aesthetic theory; it is only a political theory, that is, the important subset of moral theory that deals with the proper role of violence in social life.  .