It might be those that are antinatalist want to feel that they are sharing their beliefs with others that feel the same way. Maybe it doesn't have to be a message for those having kids but a way to feel accepted for believing that there are too many humans already and we could really do with a fuckton less.
The planet is on its way towards an extinction event and we are driving it. Some people chose not to want anything to do with children.
You can't stop someone who is determined, but you can create situations where it's inconvenient. I.e. birth control gives people choices as to when it's good to have a baby, equality in the workforce gives people a better use of their time then having a baby, lack of basic and affordable childcare and healthcare makes it very expensive to have a baby.
Antinatalism is winning. Maybe it wasn't a big conspiracy, but it's happening.
Maybe, just maybe, someone on the fence will realize that nothing they can do will offset the carbon debt and damage that bringing another human into the world will do. And then maybe, just maybe they will decide not to be some "fuck you I got mine" shithead.
It’s pretty much the same thing with the anti-work and fuck cars kids… they need something to rage about until they become mature enough to figure out how things work.
"How things work" is that the entire planet has been way over carrying capacity for decades. Humans are driving the sixth mass extinction event the Earth has ever seen.
We're quickly running out of critical resources. Shortages exacerbated by increasing extreme weather from climate change are already destabilizing regions and causing conflict. The ongoing crisis in Syria was started by the worst drought the region has seen in almost a thousand years.
Most of our adaptation efforts are insufficient, and it's more common to simply not make any effort. There are way, way too many people on the planet, and decreasing the human population is one of the most rational and effective things we can do.
If you're looking for someone who's reacting to all of this in a childish way, find a mirror.
How things work is knowing that complaining about it in a far-corner of lemmy community to a bunch of people that will predictably agree with you via a meaningless upvote is not actually doing anything at all about it.
The world won’t change regardless of how clever your memes are.