A Democrat is somebody who believes that we become liberated as a people when we are strengthened by the bonds of community; that true freedom is achieved through - not at the expense of - shared responsibility for our wellbeing as a people and as a society.
Freedom means the ability to "follow your bliss", to use one of philosopher Joseph Campbell's favorite phrases; to fully realize your creative potential as a human being in your personal and professional life; to improve the quality of bother your own life and the life of others.
By this definition, you cannot be free if you are hungry.  You cannot be free if you are consumed with anxiety about your economic future.  You cannot be free if you have been "downsized", "outsourced", or "automized out of a job, and you have no new prospects to provide for your family.  You cannot be free if you lack health insurance and are one illness away from bankruptcy.  You cannot be free if your upstream neighbor pollutes the river that supplies your drinking water.  You cannot be free if you are paralyzed by fear of violent crime.  You cannot be free if you are denied the means to a college education that would sharpen and unleash your talents.  You cannot be free if you face retirement in destitution.  You cannot be free if you have no voice in your workplace.  
As Democratic icon Hubert Humphrey put it, Democrats seek "emancipation from one's fears, his inadequacies, from prejudice, from discrimination...from poverty."
And that is why most Democrats proudly believe that an activist government is essential to preserving and enhancing our freedoms.