The spam isn’t for us to read… it’s for search engines to read. As far as search engines are concerned, every link here is an endorsement of the link’s destination.
The way pagerank algorithms work, higher-ranking sites get heavier weights in the search scoring calculations. A single link on a high-ranked site is worth thousands or even millions of links on Joe Random’s blog. So if spammers can get a link to “stick” on a popular site like BLF, it has a relatively high reward. This makes it worth a relatively large amount of effort.