I think you might be misreading some of these comments. I also wonder if you are aware of the history of eugenicist ideas in the west, and how enmeshed those concepts are in many every-day attitudes about who should be having children—often without people understanding the history (and original intention) of policies they espouse. I am not advancing any kind of conspiracy theory here.

And I think you misrepresent the potential harm. Anti-natalists don't just want to forgo having children. Many anti-natalists also want to discourage or prevent other people from having children. In fact, I'm sure many people making anti-natalist comments here do intend to have children themselves—they just want to discourage or prevent other people they find undesirable from having kids.