It's not so much that they think they are "smart"; it's that they have been paid very, very well by our corporatist conservative elite to parrot the same tired "Democrats will never be 'centrist' enough until they break off the 'left' and meet the 'American electorate' in the right-wing 'middle'!!!!" bullshit they have for the past 40 or so years. It's really all they've been taught and paid to regurgitate.