What's a legitimate site? Plenty of sites most people would call "legitimate" like high profile blogs or ecommerce sites engage in activity that's frowned upon by Google. The fact that some unwanted behaviour was no longer rewarded isn't exactly a penalty.

What RapGenius (also a legitimate site in the sense that they're not scammers and providing an useful service) did wasn't just unwanted behaviour but specifically forbidden. And yes, they're far from alone in what they did. Which is exactly why Google is making an example out of them.

I know, it sucks, all your competitors doing similar things forces you to choose between taking this risk and never making it in the first place. But that's exactly why it's a good thing Google is making a stand and setting an example.

It's a move towards a level playing field where nobody is making the internet a worse place by engaging in tricks like link farming rather than a level playing field where everyone is doing it and the end user suffers the consequences.