Super Delegate and Delegate Controversy; Why are Delegates Voting for who they Think will Win Rather than who they Want to Win?

Super Delegate and Delegate Controversy; Why are Delegates Voting for who they Think will Win Rather than who they Want to Win? I have never heard of such a thing. It is spineless to vote for who you think will win rather than who you want to win and I won't support a party that actually celebrates this type of mindset.