he's not "ideologically extreme". he played the part of the progressive to win the Dem primary, because Dem primary voters, especially in major cities, support major changes to the status quo and he proved able to say what they wanted to hear (but largely unable to do what they wanted him to do).
for otherwise-Democratic law enforcement personnel to make any kind of difference anywhere, the margin would have to be razor-thin to begin with, such that a dozen other factors could be pointed to as well.
Face it, if you stand with the 83% of Americans who want stronger regulations for Wall Street, you are ideologically extreme.
http://www.usnews.com/opinion/blogs/economic-intelligence/2013/09/16/poll-shows-americans-want-more-wall-street-regulation-five-years-after-the-financial-crisis