"And I think I outgrew “The world’s overpopulated and bad!” by the time I was about 14." Wow, condescending AND nonsensical. What the hell does this even mean? It's like saying "I outgrew climate change."

There's no point in responding to a person who's not interested in having a discussion. At this point (and, I'm sure, from the start), he's not considering, but only formulating rebuttals. (Apparently he didn't outgrow his adolescent debate style.) Why waste any more energy?

Of course, walking away will make him think he "won," but he's a half-wit and it's not a competition, so what he thinks is irrelevant. On many levels. ☺