Has not wanting kids because of the state of the world been around for a long time?

Those are two different timelines. A word’s earliest known printed use only tells us that someone used it by that point, not when the word was coined or when people first felt that way. And a historical example of someone choosing not to have children would not, by itself, show that their reason was concern about the world.

I’d be cautious about treating a single date as proof of a big cultural turning point. The account being discussed gives different dates for the word, and a date is only as solid as the document and context behind it. To show that the specific “the world is too troubled” argument became common in a particular era, you’d need examples that actually state that reason, not just an old use of the word.

The feeling can be older than the label, sure, but it’s hard to trace unless people left a clear record of why they didn’t want children. Modern fears like war or environmental danger may give the argument a particular shape in each period. That doesn’t mean the feeling started then, or that every choice not to have children comes from the same worry.