1: Autistic social outcasts will spend way, way more time on the internet than well adjusted, good posters, and as a result post far more. Because of this, they can very easily ruin threads/boards/sites if not kept in check.
2: Autistic social outcasts will tolerate shitty websites, good posters are far less likely to do so. This means that very few good posters will stick around or be interested in the site in the first place, while horrible ones are attracted to the site and impossible to get rid of.
3: The anonymous nature of the site and very lax rules means that autistic social outcasts have no worry about openly flaunting their pedophilia or anything else shameful. This also means that people who dislike pedophiles want nothing to do with them or the sites they use; pedophiles being on a site drives non-pedophiles away. Anime pedophiles also love talking about their anime kiddie porn all fucking day. You might not realize on an anonymous site like 4chan, but anywhere with accounts you can see that a lot of these people literally never shut up or do/talk about anything else.
4: Autistic social outcasts are very prone to porn use, and heavy porn addicts are always going to end up masturbating to more extreme, "disgusting" things over time as the old stuff becomes "boring". Being that 4chan is an anime website, and the users of it are anime fans, what they typically consume is anime porn. And because anime and anime porn is so inundated with pedophilic garbage, the extreme/forbidden/"exciting" content they're exposed to usually includes lolishit.
<reddit spacingAlso, IIRC, the loli board was a containment board moot made because he didn't want to see them on /a/ (the board he actually cared about, same reason he made /b/.) I'm not entirely sure about this though, I could be wrong. Pic semi-related.
>>14634713>largely because japan's age of consent was 13 up until recentlySomewhat misleading, this was the federal minimum. It was higher in most (maybe even all? My memory is lousy) of Japan. Similar to how the federal age of consent in the USA is 18, but is lower than that in most states.