Does this even need explaining? Okay: YouTube quote-unquote "sensations" have been made out of borderline-patronizing (if not fully-patronizing) coffee shop would-bes spreading onto your favorite new rap song their particular strain of twee, a la Outbreak monkey. And just like the disease that monkey in Outbreak once carried, it is very, very hard to decontaminate your mind once you've heard "Love Sosa" sung in the key of Michelle Branch, or John Mayer, as the case may be.
And it's not that cheesy people doing cheesy covers of completely not-cheesy songs didn't exist in the 90s, it's that it was very, very easy to avoid (or even acknowledge the existence of) these songs. In 2013, they are everywhere, like boogeymen hiding around every corner of YouTube, just waiting to totally fuck up "Shook Ones Pt. II" for you, for good.