Spam (and shady Search Engine Optimization) is such a profitable business these days that we get all sort of people trying to create links back to their sites. Pretty much all of them fail spectacularly, but many of them are quite annoying while they happen.
I assume this person thinks that by buddying everybody on the site, he'll be creating a link on their profile back to his, so that when he writes his spam blog posts they will have more Authority and therefore send more Google juice his way.
He's wrong, of course. And he's probably spent a lot of time posting entries to that blog, all of which have been swatted down by our spam filters. Still, it's annoying to watch.
I guess the best you can do is to simply ignore that buddy request.
Sorry for the inconvenience!