Sanders is not radical at all; he's operating under the aegis of the Dem Party who wouldn't have accepted him under their umbrella (circus tent, whatever) as a true radical. It is possible, as some say, that he serves Party purposes by running. Openly stating that he would support Hillary if she wins the primary is significant. Or perhaps he hopes to create such a groundswell of popular support for himself and his message that he can prevail - a pretty big gamble (and leaving the unresolved issues of Israel/MIC support). At any rate I find the headline framed in the bent propagandistic commentary-not-journalism mode we are all too familiar with.
I agree with the commenter who says it's a Good Thing to publish polling results that show what the US populace really wants. I'm less impressed by the absence of any mention of the public's receptivity to an openly atheist candidate which I assume has not increased like it has for various religions.
The issue of 'electability' will continue to be hotly debated. The principle of 'voting one's conscience' is still derided, and the prevailing voter view is apparently still a preference for being 'on the winning side' as if elections were a sports spectacle. To me, saying Sanders is the only electable candidate subscribing to the most pressing issues of the people is a version of less-evilism.