They are the Democrat party. They are not the Democratic Party. There is nothing democratic about them. Remember, they introduced superdelegates. Why? So the riff-raff wouldn't challenge the elites who control the party.
Also you should remember it's founding. Martin Van Buren organized their party and handed out patronage jobs to control dissent. He didn't want slavery to be discussed because it was a divisive issue. This worked until the Republican Party came along and forced the issue.