I suggest reading the sim rules/bio as well as considering leaving the area yourself before pestering people minding their own business over a predetermined rating of an sim. The letter next to a sim is a guide line of what could be expected not what isn't allowed. If a child is in a non sex-themed adult area it's no one's issue or business why they are there.
Honestly, I have the same issue with my farm being on an adult lot, I curse a lot and I like to play inappropriate music, plus I genuinely don't *want* to play with RL kids/teens. just because there is an adult rating does not mean there is *sex* happening.