Glad you already learned this is probably nonsense. The wrong reasoning is very similar to much thought about overpopulation. The amount of people that makes for a place to be overpopulated is a function of how societies work and the technologies they have at hand. One extra issue there is that improvements in technology usually lead to population growth, so much progress gets cancelled out.
One of the things I read about that, is that people tend to take an “average position” between all the opinions they hear. It used to be that the opinions you’d hear would be based on serious media, and your close circles. But much of the media has gone to shit, and social media amplify crazy people because it’s good for engagement. So you end up hearing about the crazy position of lore as much as about the rational one. And that does influence a lot of people.