1) Ghetto ethics only require that the exchange is voluntary.
2) They do not require that the exchange is productive, only that parties are satisfied. (blackmail for example is not productive.)
3) They do not require fully informed exchange backed by warranty. (they allow lying and cheating and information holding)
4) They do not prohibit profiting from harm, or causing harm (Usury for example.)
5) They do not require that the exchange is free of externality.
Parasitic ethics of rothbard require only the first, but the high trust ethics of Protestant require all five criteria. High trust ethics (and human in-group moral instinct) require that we eschew free riding (parasitism) and the only means of doing so, is to require exchanges be internally and externally productive.
Under rothbardian ethics it is possible to profit without contribution to production, and to exist entirely parasitically. ie: his ethics are parasitic.