I emailed the comm mod yesterday about it and included a link to the userprofile for the pornotroll... on checking back it appears to be the same person.... Diamondpugh was the username I emailed to her yesterday and it is the same user today. She says she banned them, so I don't know how they are posting again. It's not a super-active community so going moderated for a while doesn't seem like it would be a big deal.
This stuff comes in cycles. The "more than one user" was likely a single company or person that found an exploit or way around the system (notice how all of the spam posts across LJ by "different users" all went to the same site?). Every time the spammers figure out a new way bypass the LJ spam account protection to auto-register multiple accounts, add hundreds of communities and spam post, we see this. It's happened dozens of times over the last 10 years and it will happen again.