Legal Interns and Minimum Wage, and Libertarians

Yesterday there was an employment offer for "intern" (read that as free labor). As I understand the labor-law, you cannot have an "intern" and not pay minimum wage unless it is part of a certified educational experience or unless the work for you has either no value or negative values (in other words, the time you spend with them gets you no benefit and cost you time and effort). The (heavily redacted) add says:

We are looking for a xxxx intern to run our xxxx operations. We will train you in:

(lots of stuff redacted)
In exchange for the training and the housing you are expected to care for the needs of the:

1. 6 work things normally people would want to get paid for....

A Forbes article says:
Here are the six factors considered by the Court:

1. The internship, even though it includes actual operation of the facilities of the employer, is similar to training which would be given in an educational environment.
2. The internship experience is for the benefit of the intern.
3. The intern does not displace regular employees, but works under close supervision of existing staff.
4. The employer that provides the training derives no immediate advantage from the activities of the intern; and on occasion its operations may actually be impeded.
5. The intern is not necessarily entitled to a job at the conclusion of the internship.
6. The employer and the intern understand that the intern is not entitled to wages for the time spent in the internship.

The DOL has taken the position that for the exemption to apply, all of the factors listed above must be met.


So, (libertarian question follows): should a farmer be allowed to offer, and an intern be allowed to accept, an internship that violates the 6 aspects above? If you say NO, then is the offer not legal?