That’s not inconsistent. Hillary was popular with traditional democratic primary voters. Sanders was very popular among independents. He wasn’t beloved by Republicans, but he wasn’t the target of 20 years of bizzarely channeled hate either. We’ll never know how the campaign would have changed minds, but at the start he was nationally popular.
To get more speculative, I think a number of democratic voters were overly fixated on fighting the last war. We’ve spent so much time defending “Welfare isn’t socialism, protecting the environment isn’t communism, etc., etc.” that we were certain the right would shred an avowed socialist, that we had to stay in the “center”. But the electorate seems to have just been longing for an extreme.
All this said, if the argument is Hillary or Bernie, we’re just fighting old battles again. The larger point is the more important one: is the vision of the Democratic party a coherent, inspiring one? Is it leading us to a better place, is it speaking to all of the nation?