Prejudice - just how acceptable is it?

A friend sent me the picture to the left and I made some joking response about hoping they weren't looking for a job in customer services. I was then challenged back about prejudice. This set me thinking about it - how many people in customer service will there be with that kind of haircut? And why is that? Are companies ethically able to discriminate against sartorial choices?

The laws on discrimination have been on the basis of things which people cannot change, eg race, sex, sexuality (I accept that this is not a choice), but not on things like religion - although this appears to be coming. But the push back at my weak attempt at humour has made me question whether there are issues about choice. What is it about a pink mohican that makes the owner unsuitable for a customer service role? Is it the prejudice of the employer, or is the employer predicting what customers will think and wanting to control their own image to meet expectations? Is it right for an employer to base their employment policies on the prejudices of others, or do they have a moral duty to fight against prejudice?

There is an argument that companies have no moral duty - they are legal entities with their responsibilities set down by law. Perhaps that is the way it is, and pressure has to be brought as it has been in the past over involvement in South Africa, or unfairly traded goods.

As usual, more questions than answers!