The issue is that this guy just kind of did it without going through any of the normal check steps to make sure he was doing it right or there wouldn't be any unexpected consequences

It's also extra fucked that he essentially experimented on what are now small children's lives without any concern that it might severely impact them in unforeseen ways, for the rest of their existence. And all for questionable gain because he apparently didn't really achieve the objective of making them immune to HIV.

... You're sweeping thousands of years of technology being considered "playing God" under the rug like that's not a thing. Even though in this case, the phrase couldn't get closer to being accurate.