This is just plain ignorant. Every single place I have worked has had its share of everyday sexism and racism, and that includes how current employees act in hiring interviews. You claim to not notice these things, but what you are saying is that you don't consider those things valid differences that may affect how someone perceives your team or work environment. How can you ever confront issues in your workplace by shoving your head in the sand?
Given the way you're talking about making a hire/no-hire in five seconds, I find it incredibly difficult to buy the idea that you're not taking that into account. You're glorifying the snap-judgment hire.
Because most people do, and a good hiring process takes that into account and counterbalances it.
Appearance is important, and I've never been in an interview situation where it wasn't? Unless you're insinuating choice based on ethinicity (more aimed at _pmf_'s response to your comment). Which is completely irrelevant, as are accent/sex/other discriminatory factors that make zero difference to how someone is likely to work within a team.
As I've said in other comments, there is a serious element of external preselection based on geography and company sector, there's nothing particularly underhand going on.