The mere concept of not judging one by their appearance is difficult to imagine in this day and age and almost quite near impossible to do. It is how we as humans decode or decipher someone. If one aspect of their appearance is completely misleading to that of what one may link it to about their personality, it will still hold some link or significance to something else about them anyway. We only judge what we see based on stereotype and our own knowledge about the subject matter at hand, meaning the amount of variables and connotations one element of appearance may have is unfathomable.
Countless cultures, sub-cultures, culture tribes, groups, cults, civilisations etc. have built that of what they represent or voice around appearance, being only recognisable through that aspect or element of themselves. You could think as simply as a uniform; a man dressed as a Police Officer is more than likely to be just that. Uniform is immensely important and almost subconsciously prominent in todays society being almost everywhere and providing a sense of order to what it represents, quite reflective of what it usually is: a public service, a restaurant and so on. Being able to judge maintains order and comfort within society and one of its most important aspects to date, at that.