How is different than giving antibiotics to somebody ill? You are preventing the natural outcome, with something artificially created. I think many people when the topic is "DNA" simply over-react.
The argument is that changes to genetics bridge generations. If you kill someone with medicine they die.
If you give someone a faulty gene, it could affect exponential number of people with each generation.
It is the same with antibiotics, people that naturally would not be able to reproduce, will, so the global genetic outcome will change, and possibly something making a given person susceptible to a given infection will be passed to the next generation. But nobody, fortunately, pretends that it is a bad idea to give antibiotics to patients.
