What really annoys me most about the Ferengi is that, as the writers gleefully point out in interviews included on the special features of these DVDs, this is how they actually see western capitalism. "They're US!" giggles Ira Steven Behr. The reason the writers went to the Ferengi well at least a dozen different times for story ideas despite the spectacular unpopularity of those episodes even among hardcore liberal fans of the show (I think they're sensing the non-believable nature of the Ferengi and chafing) is because they themselves thought these characters were hilarious. They're full of elitist Hollywood certainty that the only reason we here in America function successfully is because liberal ideas intrude enough on our capitalism to put checks and balances on the evilness of our nature. It shows a deep and severely troubling misunderstanding about the root causes of anything positive in this life and a deep disrespect for the country that made it possible for them to write their indignant attitudes down and produce them...and make a lot of money off of them!
Stepping past that for a moment though...the fact that Ferengi society bears little resemblance to our own should not singularly disqualify that society from being enjoyable to view. One of the great things about any sci-fi space opera is that it provides the opportunity to see a reducto ad absurdem encased on an alien race and to criticize that segment of humanity being modeled. The Ferengi were ORIGINALLY invented as an example of what would happen if you took a human quality (avarice - our need to want things) and concentrated it. I could point to other rules of acquisition that contradict the one Stephanie S. commented on specifically (Rule #6 - Never allow family to stand in the way of opportunity or equivalently, Rule #11 - Treat people in your debt like family...exploit them). For example, rule #31: NEVER make fun of a Ferengi's mother (they obviously do love their family...at least as long as they're not getting in the way of profit), rule #1: A contract is a contract is a contract...but only between Ferengi (they will screw over anyone else, but there is one element to their economic system that is absolutely sacrosanct...once a contract is signed...it is legally binding on Ferenginar)...there are probably others. So, although I agree with my co-author on her basic objection to rule #6 and to some other disturbing trends observed in Ferengi custom (women are treated like slaves, education other than that received through apprenticeships in the cut-throat business world is discouraged, etc), it's not totally wrong to create a race of people who obey rules that are probably impossible in the real world.
The Klingons, Vulcans, Breen, Dominion, Borg Federation and Cardassians (to name a few) all have initial concepts that include elements that are completely untenable in the real world. The Vulcan devotion to logic and shunning of emotion makes it difficult to understand how they can possibly function as a family, enjoy their lives, or...for that matter...procreate consistently. The pon farr seems particularly brutal...the Vulcans DREAD it internally and it often results in deaths during combat over women. It seems that system cannot possibly produce positive population growth. The Klingons are never satisfied with stability. If they're not at war, their system descends into internal feuding because you cannot possibly die an honored death if you cannot fight some enemy, kill them, and eat their heart. How the heck they ever reached for the stars when their own ideals would lead them to tribal barbarism and no unified government is beyond me. There's an old expression: never turn your back on a Breen. Their society is closed off, mysterious and untrustworthy. It would be unimaginable why they would even want to venture out into space...what would motivate them to do so...if they want nothing to to do with what's out there. The Borg collective consciousness is an ingenious parallel to communism, but the destructive tendencies of that collective should have prevented them from becoming strong enough to be an unstoppable force.
Even the beloved good guys...the Federation...are untenable. How can a society function without currency. How does the Federation conduct business with neighboring societies (simple bartering of resources doesn't explain it...you don't see Federation citizens offering Quark locar beans or dilithium crystals when they step up to the bar for a drink)? And more importantly, how, in the space of 200 years, did humans rewrite their own intrinsic nature and suddenly throw off the need for material incentives to inspire progress and development? The point is...all of the races except a very few in Trek canon are untenable. While it's good to recognize what about each race makes that race unrealistic, we need to move past that when discussing the merits of plots driven by those races.
And even in meta discussion, we need to move past the untenable nature of individual races and analyze the untenable nature of the fans' reactions to those races. Why are liberal Trekkies so devoted to the Vulcan model of perfection by the removal of emotion (pure distilled physical logic) that they would angrily reject a Trek franchise that calls that system into question (as Enterprise did), but when confronted with an equally unbelievable race (The Ferengi) exhibiting a different fatal flaw, be completely fine with that race undergoing socio-political upheaval on a MASSIVE scale in the space of 5 years...so massive that it is impossible to believe? Why do liberal fans fail to see the flaws in all of the races? And THAT is a subject worthy of a feature article.