That is like saying why do companies and organisations need security officers because theft is illegal. Is it better for taxation to go to providing people to ensure that the law is compiled with or to pay for court cases when it isn't? I think a very good case could be made that a job which works to ensure people are not discriminated against, victimised, harrassed or excluded altogether from the workplace is more of a "real job" than making wire wheels for luxury sports cars, to use the example you quoted earlier. At a time when jobs are more scarce it is even more vital that people are treated equally.
Your comment about minorities becoming the victims of mass hatred show just how far diversity and equality understanding needs to progress. I would love it to be the case that equality and diversity officers were not needed but there is a long way to go in our society before that becomes the case.
It is strange, isn't it, how you rarely, if ever, hear women, members of minority racial groups, people with disabilities, gay, lesbian or transgendered people bemoaning the existence of diversity and equality provisions?
As an aside, on the topic of wire wheels, I needed new wheels for a bike I am restoring. I contacted the major producer of such things in the UK and received a very abrupt reply that they couldn't make the size I needed. I then contacted the Italian manufacturer of the rims and they told me that the UK company would be able to supply them. I responded that they had said they could not and the very helpful Italian people quoted me a very reasonable price, which even with the carriage charge from Italy was lower than I would have had to pay from the UK company. The only snag was the Italian company was about to take their annual holiday and would be closed for the next four weeks. It is odd how companies in countries such as Italy with four week holidays, or France with a 35 working week can compete against foreign imports yet in the UK, they go out of business. Look at the car industry. How is it that Renault, Peugeot, Citroen, WV, Mercedes Benz, Fiat, Seat etc can carry on manufacturing whereas UK companies have all gone? It has to be more than simply competition from overseas.