He's not unelectable. I mean, you can keep saying that. By all means keep saying that. Enjoy it while it lasts.
I postulate that for the sheer reasoning expressed in that quote alone, HRC is more unelectable. More HRC dems will support Bernie in the GE than Bernie supporters will support Hillary.
So speaking of electability, if the polls say Sanders doing better than HRC against Trump/Cruz, and the logic behind their supporters says Sanders' camp is more avidly opposed to HRC than the other way around, and if a spade is a spade, and if it looks like a duck and quacks like a duck...
And you can keep telling yourself that Bernie is electable. You have to look at core fundamentals and it all works against Bernie.
My biggest annoyance with Bernie's electoral math is that it is the exact same as Ted Cruz's. And by that I mean it is completely nonsensical and ******ed. There isn't this vast wealth of untapped voters at the extreme ends of the aisle who just haven't come out and voted simply because there hasn't been a pure conservative or pure progressive. Americans typically vote for a candidate that is closest to the center, which is where most Americans lie. Bernie is not a centrist. He is running a campaign that disdains moderation.
And to focus more on American voters, American voters will typically also vote for the more pragmatic choice. Voters will reject a candidate like Bernie Sanders when they realize that they will get absolutely nothing done. It's one thing to criticize Presidents like Barack Obama, Ronald Reagan, George W. Bush, Bill Clinton, etc. for failing to live up to lofty expectations, but if you look at Bernie's platform, it is filled with nonstarters that have no chance of even being considered. Even Bernie's own party is saying that it isn't going to happen. And to move onto my third reason why Bernie unelectable, this perfectly segues into that part:
Bernie's own party will not support him. This will be the same problem that a candidate like Donald Trump or Ted Cruz would face, in fears of electoral oblivion at all levels, the party will shy away from the Presidential candidate in a grotesque save yourself preservation mode. When the party shys away from its own candidate, it doesn't make the candidate look any good. It's their way of saying that they give up. They're not going to invest resources necessary to win in order to save them for future battles.
Attacks on Bernie write themselves. Bernie gives the GOP a lot to work with on health care, budget matters, taxation, social issues, etc. They will attack Bernie as someone who will raise taxes on all. They will attack him as someone who will take from the middle class to give to the lazy poor and people of color. He will spend us into oblivion. And so on. Bernie on the other hand will counter the same way he always does, by sounding like a ****ing broken record.
And finally, just look at his Iowa win. Bernie dominates in the base that he has of young millennial voters. But he will do horribly with other demographics as they get older (just like he did with the Iowa caucuses). He will dominate extreme progressive voters, but will do horribly with moderates and conservatives (again, just like what happened in Iowa) and Republicans will probably peel away more Democrats than he will with Republicans. He will dominate with black voters because blacks, rightfully so I might add, see Republican as a four letter word, but he will do poorly with whites and I find it unlikely that the likely GOP candidate (Rubio) will do as poorly with Latinos that Mitt Romney did.
If I were a betting man, if Bernie gets the nomination, it would be a massive Republican victory. Bernie would probably even lose in traditionally solid Democratic states like New York, Connecticut, and New Jersey. He would lose states that lean Democratic like Pennsylvania and Wisconsin. And he has no chance in swing states like Virginia, Florida, Ohio, Iowa, etc.
Bernie's current polling comes from the simple fact that he's a shiny new toy. It will erode once he's no longer new and people get to know him better and when attacks on him take their toll.