Because the state necessarily commits aggression, the consistent libertarian, in opposing aggression, is also an anarchist.

We must recognize that only scarce resources are ownable second, that the body is a type of scarce resource third, that the mode of acquiring title to external objects is different from the basis of ownership of one's own body.

To be an anarchist only means that you believe that aggression is not justified, and that states necessarily employ aggression. And, therefore, that states, and the aggression they necessarily employ, are unjustified. It's quite simple, really. It's an ethical view, so no surprise it confuses utilitarians.

There are any number of models artists can use to profit off of their talent and artistry. It is not up to the state to protect them from competition. Musicians can obviously get paid for performing and having their music copied and pirated helps them in this respect by making them more well known, more popular.