Bernie Sanders confuses many people because he doesn't behave like a typical politician. Most politicians on either side of the political aisle mouth the same political blather aimed at reinforcing support from their existing supporters.

Bernie is different. He tells the truth. He doesn't pretend to be something other than who he is. So if you like what he says and who he is, you would support him and if you don't you would oppose him, but at least you would know which side to be on.
Most politicians try to be all things to all potential voters. Democrats are liberal with liberal voters, and moderate with less liberal voters. Most Democrats don't try to attract conservative voters because that would turn off the liberals.
The same goes for the Republicans. They are conservative with their conservative base and a little more moderate to capture any on-the-fence conservatives.
The true conservatives, or Tea Party politicians, try not to be too moderate or they would be labeled RINOs, Republicans in Name Only, but they may come down from their high horse to get a few on-the-fence Republicans (like me), or even conservative Democrats, such as those left over Dixicrats who haven't changed their party registration.
Both parties try to vilify the other and are mostly successful with voters who like to have their biases supported. They are told by Rush Limbaugh and other political ideologues that they use "Critical Thinking" because they believe whatever BS the commentator is spouting. These are the basic fallacies of true Critical Thinking: Apple Polishing (you are so smart to agree with me) and Group Think (Think like me and not like those others).
The "Other" is the favorite enemy of the "Us." It doesn't matter which Other the "Other" is, but they are the opposite or different from the "Us."
Sanders doesn't play that game. He's wears the label "Socialist," proudly and doesn't try to change anyone's opinion about it. Since most Democrats and some Republicans are also Socialists, but avoid labeling themselves as such, Bernie is refreshing for his candor.
Will he or can he beat Hillary Clinton or Joe Biden in the Democrat primary? Probably not. Would he accept the VP slot on either one's ticket? I don't know and I'm not going to speculate on it, but I hope not. I would be disappointed if he did.
Would I vote for Bernie if he won the Democratic nomination? It depends on who the Republican candidate is, but I would consider it. Income inequality is a very serious problem. We do need to get big money out of political campaigns, and limit contributions so rich folks cannot buy candidates.
People who work hard should not be underpaid or undervalued. Let's be real about this. The 1950's, when Unions were strong, was the most prosperous time for the American middle class.
Don't be one of the "Us's" opposing unions because some of the members may get benefits they don't deserve. Most of them should not be cheated out of what they earned. The only way to bring back the middle class is to give Unions back their bargaining power with employers. This is a balance. This is a yin and yang. Once you start with the "them or us" stuff, we all lose.