at no point in his political career

That's actually not the case.

"And Sanders has long been unabashed about his socialist beliefs. “Nobody should earn more than $1 million,” he told the Burlington Free Press in 1974."

“I believe that, in the long run, major industries in this state and nation should be publicly owned and controlled by the workers themselves,” he wrote in 1976.

While statements like these might be a skeleton in another candidate’s closet, Sanders has never renounced socialism, even if his brand of it has become more moderate. “Do they think I’m afraid of the word? I’m not afraid of the word,” Sanders said of the term “socialist” in an interview with The Nation on Monday.

Sanders — pointing to high approval numbers for a higher minimum wage, pay equity for women and other issues — often argues his agenda is mainstream. “It is not a radical agenda,” he said at a breakfast for reporters last month. “In virtually every instance, what I’m saying is supported by a significant majority of the American people.”

http://www.politico.com/story/2015/07/bernie-sanders-socialist-surge-119785.html#ixzz3iRq5sfrF

He has tailored his image but not renounced his roots. Because he supports moderate reforms in the short term does not mean that his final goal isn't public control over the means of production. And ultimately it is irrelevant to the point I'm trying to make. Even if by some miracle he was to be elected president, he would not be able to accomplish a fraction of what he would like to because the system is fundamentally broken. It's corrupt, which is why having someone like Bernie to expose its corruption is a positive thing. He is showing how inadequate mainstream candidates are by comparison, even with what you think is a totally moderate and liberal set of beliefs.

You will think what you want and we won't be changing each other's minds on this. I see Bernie not as a panacea but as an opportunity. If you want to keep on with grassroots organizing of a different type and ignore Bernie's candidacy then that's your prerogative.