But livejournallers are not interested in search engines, and many choose to block them entirely. The majority of livejournals are personal rants and ramblings which are of zero commercial interest to anyone, and the only reason people choose to cross post is in order to maintain contact with existing readers who will stop reading them if they abandon LJ entirely. (It's like abandoning your facebook and expecting all of your facebook friends to follow you over to twitter instead; not going to happen.)
I used to cross post between my livejournal and a self-hosted wordpress blog and it never crossed my mind to equate that with splogging. In fact, there was a popular .org plugin named LivePress which would automatically update your livejournal at the same time as your wordpress blog, and nobody ever suggested that this was a terrible thing which would inevitably be used for nefarious purposes. After all, no splogger with half a brain would touch livejournal with a bargepole; the SEO is shocking and their permalinks involve random numbers.
Argh. I'm sorry, it just boggles my mind that wordpress.com thinks it's ok to repost other people's content to your heart's content, but repost your own, even with search engine indexing disabled, and you're automatically a spammer.