I definitely agree that Google wouldn't be so vocal about buying links, if it wasn't a real threat to the quality of their SERPs.
That being said, this particular strategy from Rap Genius most certainly does not work. There are just too many obvious signals that those links are unnatural.
Why not go for the single link, in content, without exact match anchor text, with content near the link with the text you want to rank for...
http://wiep.net/link-value-factors/
If you're gonna ask bloggers for links, start with legit outreach strategies, why open with an obvious barter. I bet broken linkbuilding http://www.brokenlinkbuilding.com/ is a treasure trove of opportunity in the lyrics vertical. or simple Start with just sharing great content that is relevant, and nurture relationships with bloggers. Why buy them off, when you have such a great web property?
For a list of more strategies... http://pointblankseo.com/link-building-strategies
why not try this strategy while your at it... It would work perfectly for Rap Genius. https://news.ycombinator.com/item?id=5688175
That's why Google has to have these scare tactics to stop people from doing them. If they didn't work then Google and you and everyone else who's up in arms over this would just ignore these links.
I can guarantee you that if you do a backlink analysis of everyone ranking ahead of rapgenius for these search terms they will have thousands of these types of backlinks.