it's not entirely unmoderated. some of the rules are being enforced fairly strictly - for example, NSFW images on SFW boards get reported and erased within minutes. blatant spammers, shills, and schizos get dealt with too. only residential IPs can post, which reduces the volume of shit quite a bit. a dedicated schizo can shit up a thread, a coordinated raid can shit up a whole board, but given the ephemeral nature of 4chan, it's like pissing in an ocean of piss.

rather, it is politically unmoderated. which is, of course, the pearl-clutching anathema.