Music rights owners bought off

So, here at last is the explanation for Universal pursuing Bolt and Sony's Grouper but not YouTube in Doug Morris's ongoing campaign against alleged copyright violation - three of the four big music rights owners including Universal took a YouTube stake (NYT) just before the Google acquisition. Would only a moron buy YouTube for fear of legal action when that moron's fellow purchasers are the main potential litigants? Either YouTube or Google (or most likely both) are a whole lot smarter than that.