I assume the account was hacked. Probably a former member that isn't on anymore, and somebody, or more likely a bot, came across his information and posted here.
The system requires a real email verification, and that cuts out a lot of the spam that uses fake email addresses. I also blocked a bunch of popular disposable email sites.
Then they have to have their first post approved, and that is often obviously spam, or a generic response to get through that step. But if it's generic, I put all their posts on approval until they prove they aren't spamming the site.
The ones that get through are reported quickly, and I get an email about it.