Lets assume that genies grant wishes literally, but will twist your words. How do you wish without unintended consequences? Typical rules of no more wishes, no resurrection, no forced love, no altering the past, can’t defy logic, can’t break physical laws, can’t create paradoxes, and can’t affect higher powers (this is one tough genie!).
Yeah, if you use the broadest possible definition, then pretty much everyone would be gone. Even if you restrict it to only adults who are aware of what they are doing and still choose to be an asshole fairly often, you would be removing a huge part of the population. Sounds like a pretty bad move to me.
That sort of thing might come close to nuking the entire species back to the stone age. Then again, that would be good for the environment in the long run. It could take like 20 000 years for the human species to fully recover from that one button press. I think I’m beginning to see some benefits… nah. Still a bad idea.