If Conor Friedersdorf wants to label Rush Limbaugh "objectionable," I'll volunteer to be the first to rise to the bait.
What is Rush Limbaugh? Is he a partisan political operative? Does he collect his paycheck from the Republican National Committee? Or is he, alternatively, an idealistic philosopher in an ivory tower, pondering obscure questions of the greater good?
No, Rush is a professional broadcaster whose livelihood is dependent on attracting listeners and advertisers to his show. Nevertheless, let us stipulate that Limbaugh is also a patriotic American who wants what is best for his country. Why, therefore, would he launch "Operation Chaos," with the stated objective of tying the Democratic primary race into an ugly knot?
Short answer: Rush believes that what is bad for the Democratic Party is good for America. (If you want to argue that point, take it up with Rush.)
My problem with your "risk-averse approach," Conor, is your apparent belief that there would be any meaningful policy difference between an Obama administration and a Clinton administration. I see no basis for such a belief. Any consideration of electing the better of the two Democrats is a non-starter, if both are equally bad -- or if each is at least so bad that there's no point trying to calculate which is worse.