@Olivier5,
No Olivier5, it says to me that people don't know he's an atheist.
I'm an active atheist, and I didn't know Sanders lack of religiousness, which means that it hasn't been made an issue yet (which makes sense during the democratic primaries).
He hasn't been challenged on this and while democratic primary contest have either overlooked it or simply don't know it, the Republicans will make a huge issue out of it during a general election.
Picture the attack ads: "Ask yourself if you want a godless socialist leading the greatest country on earth."
Now, if love it, but that **** won't play well for most of the country. I'm telling you, people don't know that side of Sanders right now. They will.