I think that's an overstatement. I don't think it's part of the democrat party platform for the government to own the means of production, for example, so describing them as communists isn't accurate at all.
They are certainly ideological kin to communists and socialists, but I don't think those words are descriptive. It's as silly as them calling conservatives 'fascists' routinely. It's just not a clear, accurate, and precise fit.
Well, considering that equality of means, fairness as determined by the state, central planning, democracy and collectivism are actually things valued by the Democrats over and above individual freedom and property rights, I think it not unfair to refer to them as socialists.
You are correct perhaps in stating that they are not socialists strictly according to the exact meaning of the word, since they are not actually (yet) calling for state control of the means of production, nor are they using the above terms. Nevertheless I do not mind seeing them referred to as socialists since at a fundamental level, their mindset is the same.
I won't argue with you if you wish to refer to them instead as leftists, and reserve the socialist tag for the few really true ones like Hillary and Pelosi. But the rest are still pushing us leftwards as hard as ever they can, in other words, toward socialism, whether they see themselves as such or no. They are all operating in the traditons from which socialism is derived.
Probably "communist" is not strictly accurate, except maybe for Hillary, but the Democrats are still closer to communism than they are to American traditions of freedom, so I for one think they deserve it when they get called commies.
I know an elderly couple who managed to escape many years ago from Rumania, which was still behind the Iron Curtain. They have had no trouble referring to Democrats as socialists, refusing to vote for them since, as they said, they already knew what it was like to live in a socialist country. The gentleman a few months ago, on hearing support from me for Bush, looked at me and said, "You like Bush? He is just a socialist too." An interesting perspective from one who had first hand experience.