He reasons that it is unfair that there appears to be a racial imbalance between the representation of various ethnicities on the database, and life would be easier for the police if everybody was on the database. This misses the point. "Fairness" should be irrelevant, because DNA testing is an objective test. If the police have a DNA sample from a crime scene and a list of suspects they can eliminate or identify each of those suspects by comparing their DNA with the DNA sample.
Having a DNA database of convicted criminals could be justified on the basis that empirical evidence shows a high level of reoffending, and hence any convicted criminal might reasonably be considered a suspect.
But to extend the database to the entire population would be offensive. Why? Because assuming a possibility of a few hundred thousand to one of an individual matching a DNA sample, then in a population of 60 million there will potentially be hundreds of people matching that sample. The odds may vary from sample to sample, but who wants to be suspected of a crime just because of a statistical fluke or even operator error. Who wants to be forced to account for their innocence of a crime when there is no other basis for suspicion? If the police have another basis for their suspicion of an individual, they don't need a DNA database, they just need to match the suspects DNA with their crime scene sample.
And to extend it to tourists and other visitors is a sure way to kill off tourism, the City of London and international business.