There's a vast chasm of difference between "right to work" and "right to be paid for your work".
Just because it's "artsy" doesn't make it more okay.
Because after all, open source gives us software for "free". Much of this software would otherwise have to be written commercially, so one can make the case that people who write software for a living deserve to be protected from this open source nonsense.
It's highly probable that for-profit bootcamps using volunteers would be in violation of the long-existing law.