Even if it weren't already a reddit-like FOSS platform from the start, intentionally, I don't see having a child free community as a bad thing, or even "reddit-like". Everyone likes having a place to vent about the way others treat them, regardless of child-having status. People who visit child free pages usually have negative interactions involving people with children, or things they are excluded from for not having children. People WITH children like visiting pages where they vent about things they're excluded from FOR having children.

Luckily, if you don't like a community, you can simply block it instead of leaving pithy negative comments about the subject matter.