I mean let’s be clear for most of Ferengi history women were not allowed to own property of any kind - including clothing and some of their business endeavors include poaching endangered animals and literally being slave traders. I mean - I don’t think there’s any indication that Ferengi society was anything more than hyper-capitalist dystopia as a juxtaposition of the Federation socialist utopia. That Rom and Quark are goofy and lovable I think speaks more to how bad every other Ferengi is operating outside of a Federation station.
From the Federation’s perspective the Ferengi are harmless and in this way they may be ethical enough to not warrant confrontation, but at the same time - the Federation does seem to stop them when they’re doing something like slave trading so I think we can imagine that for some people in the sphere of Ferengi influence they’re not so ethical.
This is a question worth asking. As others have pointed out there sort of seems to be clear that the rules are the rules and business rules trump all other rules. The Rules of Acquisition tend to be the Ferengi Alliance’s highest law. It’s both a religious law and a practical one and I think therein is where the problem lies. You can’t make profit outside of the constrains of normal ethics because whatever makes profit is what is ethical to do.
This is why so many contradictory Rules exist in this system. War is good for business and peace is good for business, and neither of these are statements on what is “bad” for business. There’s nothing here that says not to do anything and I think in this way Ferengi ethics largely comes down to there’s no precept that says I shouldn’t do this and I was able to exchange doing it for profit so ultimately it serves a higher purpose.
And since it seems like there is a fair amount of legalize extortion that happens in Ferengi while it might be technically illegal to do slavery, it might be more profitable to do it and therefore on the whole you can come out with an ethical conclusion that is “good” especially if you’re some mid-level Ferengi in charge of making sure that slavery doesn’t happen and you’re able to take a little bit of a kickback.