I think judging by appearance is unavoidable, myself. It's a natural phenomena, most easily recognized by 'sexual selection' in nature. That said, it's disappointing that humanity attempts to elevate itself above the animal kingdom... yet has difficulty abstaining from this phenomena.
For those that don't know how this kind of profiling works... think of everything you know as a taxonomic species(
If you're confused as to what I mean, check out this awesome illustration here). Now, imagine my hair as a species. My hair has specific characteristics unlike any other hairdo out there... but there's a genus of hair that shares many of my hair's characteristics in many other men; a genus that many are familiar with. That's about as far as people go when evaluating my hair, and they would no doubt harken back to an age of cannabis and fros' when they see it. Let's assume that the inclusiveness of this Genus's Family extended to female hairdos, however. Now, you have completely different stereotypes on this other side. Tied back hair becomes professional.
We all do this kind of stuff; this act of categorizing the world... but there's a point where these things... stop working. Take whales and tuna, for instance. They both have similar looking fins on the outside, but they're worlds different, in reality; whale fins are more like our hands than the tuna fins.
In short, we like to categorize things. It's great to be able to identify X based on Y, Z, and A at a glance... but Y, Z, and A doesn't always accurately find B, C, and D in something; the important stuff. It's efficient, the same way speeding is efficient for a commuter.
When I evaluate someone, I don't really care about their hairstyle. It's just an outlet. While I don't often act on what i see, I do look at how much makeup a person wears and their attire. There is a point where I'll say no to the idea of talking to them just on the basis of them looking like a painted doll; or because their shirt is "ratchet". I'm fine with neon pink pants, malodor(which is common for some reason), crazy hair, and all that other stuff. So long as you dress like an actual person and not a mannequin I'd likely be fine talking to you.
Beyond that, yes, I judge them by their facial expressions and behavior, but I also judge them just by the vibes they give off and their interest in literature. With a friend, their history comes into it.
As a country, the US has only just begun recovering from overzealous visual profiling. It's found in racism, sexism, ageism, and now, I suppose, hairism. Has it made society a better place? No, of course not. Has it made it more efficient? Absolutely. A person can profile you in seconds, or spend days evaluating you in earnest. It introduces a nasty risk of missing out on meeting a cool person, but is still handy insurance, I suppose.