The whole purpose of life on this planet is to evolve and survive. The whole secret, the key, to the survival of a species - is how well that species adapts and evolves, in the process changing to a considerable degree. You have to admit that the primitive microscopic creatures that first used DNA to gain a competitive advantage bear little resemblance to us, yet they made possibly the only significant contribution to DNA science.
For millions of years, that DNA "research" was taking place in the world, at first extremely slowly as changes were refined over uncountable millions of generations of those little tiny creatures, and disdavantageous changes were suppressed, advantageous changes enhanced, by various outside forces. The pace of change started accelerating, unnoticed by the mites and arachnids and plants and ferns, but accelerate it did. Now one species was actively interfering in the DNA of another species by eating or killing or supplanting those of the other species that were susceptible to being eaten or killed or supplanted.
It became more important to adapt quickly, or else already have an adaptation that gave a survival advantage. The more slowly your species adapted, the less likely it was that they would survive. In effect, by using large-scale methods, undesirable bits of DNA were snipped away. Some parasites actually alter the chemical structure of their host's DNA directly in order to ensure their own survival.
Now, what took countless generations of bloodshed and death to accomplish, scientists are able to achieve with genetic scissors and splicing techniques, in extremely short timespans. We are now able to treat conditions which would have killed our forefathers, and to create things that give us as a species a survival advantage, inside a generation rather than in terms of thousands of generations. How that can do "more harm than good" I cannot say, only that to my view, we are doing what evolution pressures us into - adapting ourselves and our surroundings to ensure that there will be a human race in the future - and therefore that statement is untrue.