Appearance bias in hiring, as Angry Mouse has discussed, is a feature, not a bug.
It is an unavoidable consequence of an economy where sales skills dominate.
And as such, it is only a symptom of the lack of diversity in our economy.
The loss of manufacturing, in particular, has made the American economy a monoculture. When sales and finance rushed in to fill the vacuum, they re-engineered the workplace to make salesmanship the most valuable traits in an employee-- and indeed, in human character itself.
Appearance bias makes good business sense if you're a hiring manager. (Although I would argue that it's got nothing on positive attitude bias.) You want to make your best impression; and the unconscious bias is king, for both speed and durability.
You want to do whatever it takes to maximize the power of those unconscious biases (and by the way, you've got short-term quarterly returns to fill) which means not taking chances on personalities or presentation styles that aren't a sure thing. You're going to pick the young, ever-smiling hotties, because they're easiest and safest (and usually most compliant).
The requirement to always put your best face forward is a natural consequence of service, sales and marketing taking up more and more of the economy. More workers are also expected to be in greater and greater amounts of "face time" with the public, because the only jobs that cannot be outsourced are the ones requiring personal human touch.
It is almost a universal belief that skills can be taught, but attitude cannot-- which incentivizes hiring managers to take an essentialist approach to personalities and write them off as irredeemable if they're not "the right people", Jack Welch of course being the one who elevated this to a fine art.
Lying? Unethical behavior? Often necessary. Even redefined as proper professionalism. Because allowing a negative impression to be cast on your company image is by far the worse sin. Each customer who has a negative experience will tell three friends, who each in turn will tell five friends, etc. ... and it takes ten positive messages to equal one negative one.
Everyone who has ever worked in customer service or retail is familiar with this rule, and it is singularly unarguable. There is simply no way to dissent with this idea, without coming across as an unhelpful malcontent.
Instead of the tangible, measurable progress of a manufacturing job, our success or failure in any sales job hinges on one thing: the reaction of the consumer. It makes little sense to feel confidence in your communication skills, when nothing means what you think it means; nay, meaning itself is dependent on the response you get. And if there's one thing we know about others' reactions and feelings: we have little to no control over them. But our culture of salesmanship assume we have full, 100% control. And assigns us full responsibility if things go wrong.
The cognitive dissonance and confusion as to whether this is truthful-- or even healthy-- in real-life interactions, means nothing to a manager looking to fulfill a sales quota or woo a client. After all, they've got people higher up the food chain pressuring them to close every sale, every time; people who got to the top by being the best spokesmodels of all, by having the swiftest and most highly refined instincts for image preservation.
When you have to be constantly selling to survive, there simply is no room for balance or reflection. There also is very low trust of others, because no social interaction exists that does not have an ulterior motive. Traits of highly successful salespeople-- charisma, good looks, extroversion-- become unquestioningly "good" and unchecked for any possible side effects or means-to-end dilemmas. Sociopathy itself becomes selected for as a success trait: because, once again, empathy for others takes too much time, and telling the truth may lose you the sale.
An agricultural monoculture requires massive doses of pesticides and fertilizers to keep it functioning at barely adequate; and it still remains vulnerable to complete destruction by one good insect attack or disease infestation.
An economic monoculture puts emphasis on ONE ideal set of character and personality traits, devaluing the contributions and human potential of not those who don't fit this mold, but those who do fit it; by effectively reducing their productive tenure. It makes us one-trick ponies in our careers, un-resilient in the face of adversity and unable to muster the perspective necessary to solve many problems.
Both types of monocultures drain the respective environments dry, making what remains inhospitable for all who come afterwards. It's time to replenish the soil.