This is overblown. Nearly all "the entire gene pool" lacks this particular mitochondrial defect. The population who have it, have a great deal of trouble reproducing. This procedure allows them to reproduce without passing on the defect. Unless some other trait has been previously limited to this population and will now be passed on to viable descendants at a higher rate, the effect is very small. Unless that particular trait is so advantageous that those descendants will outcompete all other humans, it certainly won't have "consequences on the entire gene pool."
