If you're worried about links perhaps you would be better off starting your own worksafe imageboard instead of staying on 4chan with "Cool stuff from J-List" linked right on this page ir NVDOUJINS, THE FREE DOUJIN LIBRARY, or the links to the zomg pronz across the navbar.
Besides, in 2002 the Supreme Court of the US ruled that lolikon is legal as long as it isn't indistinguishable from a real child because it falls under free speech. The 18 and over only applies to pornstars because they need to be of age to consent to be recorded performing sexual acts. Because they aren't real, drawings can't give consent nor should they be required to under the law. If someone gets off on it it is a moot (lol) point because it is already against the law to harm children. You can ban lolikon when watching people get killed, raped, humiliated or tortured in movies and television is banned. Seig Heil.
Meanwhile Canada will ban your delicious flat chest doujinshis as child pornography, but apparently REAL 14 years olds are a-ok! Ha.