This is a mischaracterization. 4chan was founded as a new place for Something Awful anime fans to post hentai and "loli" content after SA banned such things. It

This is a mischaracterization. 4chan was founded as a new place for Something Awful anime fans to post hentai and "loli" content after SA banned such things. It was always about contraband and bad-taste culture. The "dirtbag free speech" crowd flocked to it because of the side-effect of that initial culture being anti-moderation and being allowed to post whatever they wanted.